Removed the call to fugitive 'helptags'

There's no reason to really run this every time vim starts.  Fugitive
provides the :Helptags command, which can be run manually
Removed python-mode plugin

It's a little heavy weight for my tastes, and I'm only really using it a
couple features from it.
Removed python-mode settings & added in breakpoint function

The breakpoint function & shortcut was one of the things I found useful
from pytho-mode. I've added it back into my ftplugin/python.vim
Installed jedi plugin.

Jedi's code completion seems to be pretty good. This was the other
feature I actually used from python-mode.
Reorganized vimrc a bit
A version of wombat colorscheme that works in the terminal
Added some options taken from vim-sensible