Changing the file navigation plugin in use

Also did the following:
1. Changed the easymotion prefix to <Leader>m because this conflicted with a
shortcut used by the Command-T plugin
2. Removed the 'FuzzyFinder' plugin
Disabling the YouCompleteMe plugin for now

I couldn't get it to work well with the new version of Python against which vim
is linked.
Adding man pages for gnu coreutils from Homebrew