More code metrics. Satisfy cane.
Remove metric_fu (and half of Rails, apparently).
Add cane
Add churn
Allow ruby-head to fail on Travis CI

https://github.com/travis-ci/travis-ci/issues/1195
Allow *ruby*-head to fail on Travis-CI!
Merge pull request #1 from johnsyweb/more-code-metrics

More code metrics. Satisfy cane.