Define leader key first to allow for vim/plugins/.
Remove dead vim plugin config.
Split plugin_config up into multiple files.

`Bundle` and mappings are coming along for the ride.
Rename keybindings.vim to mappings.vim
Move MacVim tweaks directly into gvimrc.
Bump MacVim's font size.
Remove vim-rooter. I start Vim in the right dir anyway.
Move vimrc into vim/config/ files.