API/ENH/COMPAT: compat for datetime.time via Timedelta
Now that `Timedelta` is a full fledged type. It is quite trivial to convert a `datetime.time` to a `Timedelta`.

pros:
- highly performant
- very similar output
- no need to create a `TimeBlock`

cons:
- no longer a `datetime.time` instance (instead its a sub-class of `datetime.timedelta`)
- doesn't support `tz`(anyone actually use this 'feature')?
- negative times would be allowed (eg. I think this is not allowed for `datetime.time`).

So either we go full-fledged and create a `Time` scalar and `TimeBlock` (though `TimeIndex` could work w/o these.). Its possible to also create a `TimeBlock` and NOT create a `Time` scalar.

That said creating a `Time` scalar is very easy and much simpler than `Timedelta` and shares a lot of code.

```
In [28]: s = Series([datetime.time(12,0,0),datetime.time(14,1,2),datetime.time(2,0,1)])

In [29]: s
Out[29]: 
0    12:00:00
1    14:01:02
2    02:00:01
dtype: object

In [30]: pd.lib.infer_dtype(s)
Out [30]: 'time'

In [31]: s.iloc[0]
Out[31]: datetime.time(12, 0)

In [32]: s.apply(lambda x: pd.Timedelta(seconds=x.hour*3600+x.minute*60+x.second,microseconds=x.microsecond))
Out[32]: 
0   12:00:00
1   14:01:02
2   02:00:01
dtype: timedelta64[ns]

In [32]: s.apply(lambda x: pd.Timedelta(seconds=x.hour*3600+x.minute*60+x.second,microseconds=x.microsecond)).iloc[0]
Out[32]: Timedelta('0 days 12:00:00')
```

thoughts?

Is `datetime.time` really THAT different from `datetime.timedelta` that it SHOULD be a full-fledged type?
