Update PDF documentation to Stable version 0.12.0
This seems to be a very common issue with Python projects (Numpy has the same issue).

If you try to download this:
http://pandas.pydata.org/pandas-docs/stable/pandas.pdf
You'll get the documentation for version 0.11.0

Check the links for the pdf documentation at the main web page here:
http://pandas.pydata.org/
The same problem...

Here:
http://pandas.pydata.org/pandas-docs/stable/
Again...

This might be a detail (maybe docs don't change too much), but I expect the pandas project to be of high quality!

Besides, there are a lot of people that don't have an internet connection available all the time (lots of my students don't). Therefore, being able to download a PDF to read it offline is good. Also some people prefer to read PDFs instead of a long web page...  
