Removed and ignored Gemfile.lock

See http://yehudakatz.com/2010/12/16/clarifying-the-roles-of-the-gemspec-and-gemfile/
Revert bcc1384 and 655a297

Will merge the PR manually so that the right person gets credit for the
changes.
Merge pull request #196 from rmm5t/remove-gemfile-lock

Remove and ignore Gemfile.lock