[vim] Cleaned up .vimrc, added a few unite settings.
[vim] Installed a few plugins.
[vim] Changed localleader to ,
[vim] Changed a vimux setting.
[vim] Changed Ultisnips mapping to not use the same as YCM.
[vim] Added settings for rainbow parentheses plugin.
[vim] Added color settings.
[vim] Reenabled relativenumber for ruby ft.
[vim] Added aucommand which always maximizes help splits.
[vim] Minor fixes.