pydata/pandas — pull request #3003 by jreback (2013-03-10 18:30:29+00:00)
Title: BUG: fixed value_counts with datetime64[ns], GH 3002

Fixes issue 3002

- Fixed for datetime64[ns]
- Fixed for timedelta64[ns] (though the returned index
is actually int64, which is wrong, should make a TimeDeltaIndex class....someday)
- Fixed NaT display in a DateTimeIndex (was displaying funny)

```
1 2010-01-01 00:00:00
2 2009-01-01 00:00:00
3 2008-09-09 00:00:00
Name: dt, dtype: datetime64[ns]

2010-01-01 2
2008-09-09 1
2009-01-01 1
dtype: int64

[2010-01-01 00:00:00, ..., 2009-01-01 00:00:00]
Length: 3, Freq: None, Timezone: None
```

WIth NaTs
```
0 2010-01-01 00:00:00
1 2010-01-01 00:00:00
2 2009-01-01 00:00:00
3 2008-09-09 00:00:00
4 NaT
dtype: datetime64[ns]

2010-01-01 2
2009-01-01 1
NaT 1
2008-09-09 1
dtype: int64

[2010-01-01 00:00:00, ..., 2008-09-09 00:00:00]
Length: 4, Freq: None, Timezone: None
```