Issue title: astropy time format error
 Issue body: Dear Astropy developer, 
I just updated my astropy to 1.0.dev10836. But I have the error when I creating time object. The message says:

```
>>> astropy.time.Time('2000-01-01 12:00:00.0',format = 'iso' ,scale='utc')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/jingluo/anaconda/lib/python2.7/site-packages/astropy-1.0.dev10836-py2.7-macosx-10.5-x86_64.egg/astropy/time/core.py", line 194, in __init__
    self._init_from_vals(val, val2, format, scale, copy)
  File "/Users/jingluo/anaconda/lib/python2.7/site-packages/astropy-1.0.dev10836-py2.7-macosx-10.5-x86_64.egg/astropy/time/core.py", line 236, in _init_from_vals
    self._time = self._get_time_fmt(val, val2, format, scale)
  File "/Users/jingluo/anaconda/lib/python2.7/site-packages/astropy-1.0.dev10836-py2.7-macosx-10.5-x86_64.egg/astropy/time/core.py", line 274, in _get_time_fmt
    raise ValueError('Input values did not match {0}'.format(err_msg))
ValueError: Input values did not match the format class iso
```

Can someone help me with this?

 Comments: 
 Comment 0: @luojing1211 Could you print out your `astropy.__githash__`?  This works for me in the latest master--have you tried updating?

 Comment 1: Here it is,

``` python
>>> astropy.__githash__
u'de7f4829a94c8e17c89c746007fe50fbbd6fe0e7'
```

Should I update it again?

 Comment 2: I already update it to dev11111

``` python
>>> import astropy
>>> astropy.__version__
'1.0.dev11111'
>>> astropy.__githash__
u'bc59a2aaa4c6788b412a4a49b01cf0908fb5cdaa'
```

But the error is still there. 

``` python
>>> t.Time('2000-01-01 12:00:00', format='iso', scale='utc')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/jingluo/anaconda/lib/python2.7/site-packages/astropy-1.0.dev11111-py2.7-macosx-10.5-x86_64.egg/astropy/time/core.py", line 193, in __init__
    self._init_from_vals(val, val2, format, scale, copy)
  File "/Users/jingluo/anaconda/lib/python2.7/site-packages/astropy-1.0.dev11111-py2.7-macosx-10.5-x86_64.egg/astropy/time/core.py", line 235, in _init_from_vals
    self._time = self._get_time_fmt(val, val2, format, scale)
  File "/Users/jingluo/anaconda/lib/python2.7/site-packages/astropy-1.0.dev11111-py2.7-macosx-10.5-x86_64.egg/astropy/time/core.py", line 273, in _get_time_fmt
    raise ValueError('Input values did not match {0}'.format(err_msg))
ValueError: Input values did not match the format class iso
```

 Comment 3: (@luojing1211 just as an aside, you can put code examples in GitHub inside triple-backquotes as demonstrated [here](https://help.github.com/articles/github-flavored-markdown/#fenced-code-blocks)--it's especially funny when _not_ doing this with Python interpreter prompts because the `>>>` gets parsed as a blockquote inside a blockquote inside a blockquote)

 Comment 4: Still works for me.  Though we haven't ruled everything out yet.  What version of Numpy do you have?

It seems like [this line](https://github.com/astropy/astropy/blob/master/astropy/time/core.py#L270) is catching all `ValueError` and `TypeError` and dropping them, which in this case is probably hiding from us what the real issue is.  If you want to edit that file to change the line after that from `pass` to `raise` it might tell us  something useful.

 Comment 5: My numpy is 1.8.1
I made the change you suggested. And here is the result. 

```
>>> import numpy as np
>>> np.__version__
'1.8.1'
>>> import astropy.time as t
>>> t.Time('2000-01-01 12:00:00.0',format = 'iso' ,scale='utc')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/jingluo/anaconda/lib/python2.7/site-packages/astropy-1.0.dev11111-py2.7-macosx-10.5-x86_64.egg/astropy/time/core.py", line 193, in __init__
    self._init_from_vals(val, val2, format, scale, copy)
  File "/Users/jingluo/anaconda/lib/python2.7/site-packages/astropy-1.0.dev11111-py2.7-macosx-10.5-x86_64.egg/astropy/time/core.py", line 235, in _init_from_vals
    self._time = self._get_time_fmt(val, val2, format, scale)
  File "/Users/jingluo/anaconda/lib/python2.7/site-packages/astropy-1.0.dev11111-py2.7-macosx-10.5-x86_64.egg/astropy/time/core.py", line 269, in _get_time_fmt
    self.in_subfmt, self.out_subfmt)
  File "/Users/jingluo/anaconda/lib/python2.7/site-packages/astropy-1.0.dev11111-py2.7-macosx-10.5-x86_64.egg/astropy/time/core.py", line 1294, in __init__
    self.set_jds(val1, val2)
  File "/Users/jingluo/anaconda/lib/python2.7/site-packages/astropy-1.0.dev11111-py2.7-macosx-10.5-x86_64.egg/astropy/time/core.py", line 1731, in set_jds
    self.scale.upper().encode('utf8'), *iterator.operands[1:])
  File "erfa_time.pyx", line 304, in astropy.time.erfa_time.dtf_jd (astropy/time/erfa_time.c:3365)
ValueError: Buffer has wrong number of dimensions (expected 1, got 0)
>>>
```

 Comment 6: @luojing1211 Thanks, that's useful.  Pinging @jwoillez who might have some thoughts on this.  I believe this is related to a known issue in Numpy 1.8, though I think there's supposed to be a workaround for this.

 Comment 7: I may be having a similar issue, but with SkyCoord:

from astropy.coordinates import SkyCoord

dumps with:

ValueError: Input values did not match any of the formats where the format keyword is optional [u'astropy_time', u'datetime', u'jyear_str', u'iso', u'isot', u'yday', u'byear_str']

Am running numpy 1.9.0

X

 Comment 8: Ah, a clean and rebuild did the trick:

git clean -fxd
 Comment 9: It's also an unrelated issue.  The original issue seems to relate to a Numpy compatibility issue, though I have not confirmed this yet.
 Comment 10: I tried git clean -fxd. If works if I put the argument "format". It works
fine. But If I did not put "format",  it will break. I think that problem
will course trouble when import astropy. coordinate.
"""
>>> import astropy.time as t
>>> t.Time('2000-01-01 12:00:00.0',format = 'iso' ,scale='utc')
<Time object: scale='utc' format='iso' value=2000-01-01 12:00:00.000>
>>> t.Time('2000-01-01 12:00:00.0',scale='utc')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File
"/Users/jingluo/anaconda/lib/python2.7/site-packages/astropy-1.0.dev11111-py2.7-macosx-10.5-x86_64.egg/astropy/time/core.py",
line 193, in __init__
    self._init_from_vals(val, val2, format, scale, copy)
  File
"/Users/jingluo/anaconda/lib/python2.7/site-packages/astropy-1.0.dev11111-py2.7-macosx-10.5-x86_64.egg/astropy/time/core.py",
line 235, in _init_from_vals
    self._time = self._get_time_fmt(val, val2, format, scale)
  File
"/Users/jingluo/anaconda/lib/python2.7/site-packages/astropy-1.0.dev11111-py2.7-macosx-10.5-x86_64.egg/astropy/time/core.py",
line 269, in _get_time_fmt
    self.in_subfmt, self.out_subfmt)
  File
"/Users/jingluo/anaconda/lib/python2.7/site-packages/astropy-1.0.dev11111-py2.7-macosx-10.5-x86_64.egg/astropy/time/core.py",
line 1590, in __new__
    'astropy Time type.'.format(cls.name))
TypeError: Input values for astropy_time class must all be same astropy
Time type.
"""

On Tue, Jan 13, 2015 at 9:52 AM, Erik Bray <dukemichelle@example.com> wrote:

> It's also an unrelated issue. The original issue seems to relate to a
> Numpy compatibility issue, though I have not confirmed this yet.
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/astropy/astropy/issues/3237#issuecomment-69765819>.
>
 Comment 11: @luojing1211 - this is very weird indeed. Since for numpy <=1.8 there were some issues with scalar vs more dimensions, could you try:
```
t.Time(['2000-01-01 12:00:00.0'],scale='utc')
```
 Comment 12: p.s. Sadly, I cannot reproduce the error on my Debian machine, even with numpy 1.8.1 (I'm at astropy 1.0.dev11388).
 Comment 13: I tried 
```
t.Time(['2000-01-01 12:00:00.0'],scale='utc')
```

It is still show the same error. By the way, I am at the version of 1.0dev111111
 Comment 14: I updated my astropy version to '1.0.dev11395'. But it still gives the error. Is it possibly a Mac issue?

 Comment 15: I can't reproduce it either.  Where did your copy of Numpy come from?

 Comment 16: @luojing1211 Also, as it seems you are building Astropy from source, what version of Cython are you using?  It's conceivable your version of Cython has a bug (it would not be the first time that's happened).
 Comment 17: My Numpy should come from pip and my Cython version is 0.20.1
 Comment 18: It looks like you're using Anaconda though.  I suspect there's something wrong with your Numpy installation--maybe try removing all installations of Numpy and Astropy and reinstall Numpy using conda.
 Comment 19: I somehow used both. but I think pip install the package to conda. But I
will try it.

-Luo Jing

On Thu, Jan 15, 2015 at 11:54 AM, Erik Bray dukemichelle@example.com
wrote:

> It looks like you're using Anaconda though. I suspect there's something
> wrong with your Numpy installation--maybe try removing all installations of
> Numpy and Astropy and reinstall Numpy using conda.
> 
> —
> Reply to this email directly or view it on GitHub
> https://github.com/astropy/astropy/issues/3237#issuecomment-70129647.

 Comment 20: I reinstalled numpy and astropy. It is working now. Thank you. 

 Comment 21: Ok, great! Closing this issue.

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