apply on np.datetime col doesn't upconvert to Timestamp
``` python
import pandas as pd

s = pd.Series(pd.date_range(start="2000/1/1", freq="D", periods=10))
s.apply(lambda x: x.date())

# AttributeError: 'numpy.datetime64' object has no attribute 'date'
```

This is an error from some unit tests. Did something major change with how datetimes are handled? I recall that np.datetime64 was autoboxed into Timestamps. 

I'll update after poking around. 
