Updated vimrc and moved the files to .vim instead

-Moved vimrc to $VIM instead of $HOME.
-Moved GUI settings to gvimrc
-Added bundle NeoSnippet
-Replaced markdown plugin with just a simple filetype check and reset
 it to markdown.
-Removed TAB keybinding for NeoComplete for NeoSnippet, use <C-N> and
 <C-P> instead.