date_range default calendar day return
#### Code Executed:

```
#0.000016 second less than 24 hours, acrossing 2 calendar day.
print pandas.date_range(start='2016-03-22 12:19:49.053501', end='2016-03-23 12:19:49.053485')
```
#### Output of different versions.
- **Prior to 0.17**<br>
  Prior to 0.17 versions, I tested 0.16 and 0.13, they both return two days.<br>
  `DatetimeIndex(['2016-03-22 12:19:49.053501', '2016-03-23 12:19:49.053501'], dtype='datetime64[ns]', freq='D', tz=None)`
- **V0.17 & 0.18**<br>
  Returns one day only<br>
  `DatetimeIndex(['2016-03-22 12:19:49.053501'], dtype='datetime64[ns]', freq='D')`

On the [documentation](http://pandas.pydata.org/pandas-docs/stable/generated/pandas.date_range.html?highlight=date_range#pandas.date_range), the **freq** is set to be **calendar daily** by default, the test above covers two calendar days, does it make more sense to return two days like the earlier versions do?
