(CPR-55) Add rubocop to the Gemfile
(CPR-55) Disable some less helpful cops for rubocop

This was largely borrowed from the puppet repo. It enables several style
cops that are disabled there.
(CPR-55) Remove Gemfile.lock and add to .gitignore

The Gemfile.lock is causing problems because we won't have the same gems
on 1.8.7 and other rubies thanks to rubocop. This commit removes the
Gemfile.lock and adds it to the .gitignore to avoid this issue.
Merge pull request #318 from haus/ticket/master/cpr-55-rubocop

(CPR-55) Add rubocop to packaging repo