More stuff (Yay!)

-Replace powerline with airline (much faster)
-python-mode:
 -Disable lint, use syntastic for that
 -Other stuff
-ctrl-p: don't use find command, wildignore wasn't working
-cscope:
 -Add a lot of shortcuts
 -Improve database import
-Add NERDTree plugin
-Add fugitive plugin
-Buffers are no longer closed when its window is closed