BUG/VIS: rot and fontsize are not applied to timeseries plots

In some plots, ``rot`` and ``fontsize`` arguments are not applied properly.

- timeseries line / area plot: ``rot`` is not applied to minor ticklabels, and ``fontsize`` is completely ignored. (Fixed to apply to xticklabels)
- kde plot: ``rot`` and ``fontsize`` are completely ignored. (Fixed to apply to xticklabels)
- scatter and hexbin plots: ``rot`` and ``fontsize`` are completely ignored. (Under confirmation)

```
import pandas as pd
import numpy as np

df = pd.DataFrame(np.random.randn(10, 4), index=pd.date_range(start='2014-07-01', freq='M', periods=10))
df.plot(rot=80, fontsize=15)
```

### Current Result
![figure_ng](https://cloud.githubusercontent.com/assets/1696302/3709379/7841977e-1454-11e4-8396-fc42e943d54a.png)

### After Fix
![figure_ok](https://cloud.githubusercontent.com/assets/1696302/3709380/7cc1037a-1454-11e4-9456-a9335907473b.png)