Use 'rbx' on Travis.
Removed Gemfile.lock.
Use rbx-2.2.1 because RVM still isn't updated.
Added gems for platforms :rbx.
Removed gemfiles/Gemfile.rails-3.2.13.lock.
Added rbx-developer_tools dep for coverage.
Added rubysl-test-unit.
Added platforms :rbx for gemfiles/Gemfile.rails-3.2.13.
Merge pull request #181 from brixen/master

Changes to pass tests on Travis with Rubinius