Updating documentation according to the pymode vim module.

Originally from
https://github.com/klen/python-mode/blob/ed513e80d5/doc/ropevim.txt
Merge pull request #21 from mcepl/documentation

Updating documentation according to the pymode vim module.
Added 'we have moved' block at top
Cleaned up formatting to something the GitHub can render
Merge pull request #27 from digitalrounin/we_moved

We moved