Tarball of pandas-0.17.0 on PyPI contains crash in parser.c
I experienced a crash in 0.17.0 when using a pandas that's built from PyPI:

```
import pandas as pd
import StringIO
f=StringIO.StringIO("id\n2015091624765185258700105041865\n")
pd.read_csv(f)
==> Segmentation Fault
```

I traced it to a null pointer dereference in parser.c as found in the tarball that's
on PyPI. It does not appear in a parser.c if I rebuild from parser.pyx
(IOW, it's not reproducible in a build of 0.17.0 from GitHub).

Is it possible that invalid cython generated files snuck into the 0.17.0 release?

This is the valgrind output which points at parser.c line 20849:

```
==26809== Invalid read of size 1
==26809==    at 0x4C2F122: strlen (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==26809==    by 0x49C261: PyString_FromString (in /home/brian/bin/ipython-venv2/bin/python2)
==26809==    by 0xC641706: __pyx_f_6pandas_6parser__try_int64 (parser.c:20849)
==26809==    by 0xC658442: __pyx_f_6pandas_6parser_10TextReader__convert_with_dtype (parser.c:12372)
==26809==    by 0xC64893A: __pyx_f_6pandas_6parser_10TextReader__convert_tokens (parser.c:11744)
```

If you look at that line, the __pyx_v_word variable will be NULL.

```
$ python -c 'from pandas.util.print_versions import show_versions; show_versions()'

INSTALLED VERSIONS
------------------
commit: None
python: 2.7.9.final.0
python-bits: 64
OS: Linux
OS-release: 3.19.0-32-lowlatency
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8

pandas: 0.17.0
nose: None
pip: 1.5.6
setuptools: 12.2
Cython: 0.23.4
numpy: 1.10.1
scipy: None
statsmodels: None
IPython: 4.0.0
sphinx: None
patsy: None
dateutil: 2.4.2
pytz: 2015.7
blosc: None
bottleneck: None
tables: None
numexpr: None
matplotlib: None
openpyxl: None
xlrd: None
xlwt: None
xlsxwriter: None
lxml: None
bs4: 4.4.1
html5lib: 0.999
httplib2: None
apiclient: None
sqlalchemy: None
pymysql: None
psycopg2: None
```
