Updated README - git clone url bug

Seems like: git clone git://github.com/AlanQuatermain/Go.tmbundle.git
Should be git clone git://github.com/AlanQuatermain/go-tmbundle.git

$ git clone git://github.com/AlanQuatermain/Go.tmbundle.git
Cloning into 'Go.tmbundle'...
fatal: remote error: 
  Repository not found.