Refactored vimrc and added new plugins

-Refactored vimrc to look better and cleaner.
-Changed Vundle plugin manager to NeoBundle.
-CPP specific plugins now load if the file is actually c or cpp.
-Removed leader key of <leader>d since using ctags will do the same
 by pressing CTRL + ].
-Added ctags support.
-Added minimum window width.