vimrc: Fixed typo with pymode_lint_on_write
vimrc: python-mode: enable pylint running on save
vimrc: move python key bindings to ftplugin/python.vim
python.vim: added key maps for next and previous error
Moved shell mode configuration to ftplugin/sh.vim
Move gitcommit configuration to ftplugin/gitcommit.vim
Moved rest of python configuration to ftplugin/python.vim,

Leaving just python-mode configuration