Use symlinks to install

git-svn-id: http://svn.shatow.net/shells@245 ea227b21-592c-dd11-b15d-00012992a58a
Convert to git checkout

git-svn-id: http://svn.shatow.net/shells@246 ea227b21-592c-dd11-b15d-00012992a58a
Install vim-ruby into .vim/bundle as a submodule
Add git-prompt as a submodule