mistune missing in pip install dependencies

[lunemec]

Mistune module is missing from pip installer and the pyvim crashes after opening a file.

[lunemec]

Added mistune to setup.py:
#35

[lunemec]

It seems that mistune is not dependency for pyvim after all. It gets loaded as a plugin by pygments when you have ipython installed for ipython's markdown parsing. This is rather unfortunate because most python developers have ipython installed. However I removed the mistune from the pull request.