Added selenium standalone to composer and locked the versions for stability and to ensure we get tarballs and not checkouts.
I also added a seleniumvagrant profile to behat tests so I could run FF tests against a vagrant install and included instructions in the readme for runnign a selenium node to control.
Minor fixup of vagrant port info in behat README
Merge pull request #543 from jrjohnson/behatsetup

Behat composer and vagrant selenium