update vim snippet for plugin definition with Vundle.vim

Vundle has changed it's public API.  The Bundle command is deprecated.  See
https://github.com/gmarik/Vundle.vim/blob/v0.10/doc/vundle.txt#L372
Merge pull request #361 from lucc/vundle-api-change

update vim snippet for plugin definition with Vundle.vim
add snippet descriptions
add snippet descriptions