Vim: make split natural
Vim: disable plugins, change font
Vim: a few plugin changes

 * vim-airline replaces vim-powerline, which is native and lightweight
 * YouCompleteMe replaces neocomplcache, supertab, jedi
 * UltiSnips replaces snipmate
 * Remove configs of deleted plugins
Tweaks
Vim: add custom ultisnips snippets
Vim: more keymapping