Use neosnippet

ref.
  http://d.hatena.ne.jp/osyo-manga/20131016/1381934670
  https://github.com/Shougo/neosnippet.vim/tree/a7c05372bad5408ab3e87851330bbac4b5a646fd#neobundle
Add neosnippet configurations

ref. https://github.com/Shougo/neosnippet.vim/tree/a7c05372bad5408ab3e87851330bbac4b5a646fd#configuration