Timestamp doesn't correctly localize datetime.date
In 0.10.1, Timestamp constructor seems to have an issue localizing datetime.date objects.

```
In [19]: import datetime

In [20]: datetime.date(2013, 3, 9)
Out[20]: datetime.date(2013, 3, 9)

In [21]: d=datetime.date(2013, 3, 9)

In [22]: Timestamp(d, tz='US/Pacific') == Timestamp(d).tz_localize('US/Pacific')
Out[22]: False

In [23]: Timestamp(d, tz='US/Pacific')
Out[23]: <Timestamp: 2013-03-08 16:00:00-0800 PST, tz=US/Pacific>
```
