x_compat has no effect
When trying to use x_compat on an x-axis with string indicators the use of x_compat has no effect. What I would like is the plot to show every x-value and twist the angle, like in the corresponding [visualization example](http://pandas.pydata.org/pandas-docs/stable/visualization.html#suppressing-tick-resolution-adjustment).
#### Code Sample

```
posts.plot(figsize=(8,6), fontsize=10, x_compat = True);
```
#### Output

![x_compat](https://cloud.githubusercontent.com/assets/7460499/15272687/952dc4c2-1a81-11e6-95a7-8160c1443c3f.png)
#### `pd.show_versions()`

---

commit: None
python: 3.5.1.final.0
python-bits: 64
OS: Windows
OS-release: 10
machine: AMD64
processor: Intel64 Family 6 Model 58 Stepping 9, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None

pandas: 0.18.1
nose: 1.3.7
pip: 8.1.1
setuptools: 20.7.0
Cython: 0.24
numpy: 1.10.4
scipy: 0.17.1
statsmodels: None
xarray: None
IPython: 4.2.0
sphinx: 1.3.1
patsy: 0.4.1
dateutil: 2.5.3
pytz: 2016.4
blosc: None
bottleneck: 1.0.0
tables: 3.2.2
numexpr: 2.5.2
matplotlib: 1.5.1
openpyxl: 2.3.2
xlrd: 0.9.4
xlwt: 1.0.0
xlsxwriter: 0.8.6
lxml: 3.6.0
bs4: 4.4.1
html5lib: 0.9999999
httplib2: None
apiclient: None
sqlalchemy: 1.0.12
pymysql: None
psycopg2: None
jinja2: 2.8
boto: 2.40.0
pandas_datareader: None
