Update YouCompleteMe submodule.
Update syntastic submodule.
Update tcomment_vim submodule.
Update ultisnips submodule.
Update vim-easymotion submodule.
Update vim-snippets submodule.
Improve git tree alias.
Update YouCompleteMe submodule.
Update syntastic submodule.
Update tcomment_vim submodule.
Update vim-snippets submodule.
Add update script for YCM.