Improve neosnippet settings

- Add key map to trigger neosnippet expand in visual mode
- Do not load default snippet sets
Add dependencies to NeoBundle module entry
Fix: Exclude vimfiler buffer from mkview and loadview to avoid a problem make vimfiler not working

see: https://github.com/Shougo/vimfiler.vim/issues/104
Remove tab:no-current unite source from 'gb'
Update .gitignore