fix minor typo in help text
Merge pull request #498 from lumbric/master

fix minor typo in help text
Update README.md vundle installation instructions

[vundle is undergoing interface changes](https://github.com/gmarik/Vundle.vim/blob/master/doc/vundle.txt#L372-L396)
Merge pull request #499 from steve0hh/patch-1

Update README.md vundle installation instructions
Merge branch 'master' of https://github.com/bling/vim-airline