Map Rails 4 testing directories to rake tasks

This adds the Rails 4 idiom of creating test directories named "models" and "controllers" (in lieu of "unit" and "functional") to the pattern matches when running `:Rake`:, selecting the appropriate rake task to run.

This allows those doing Rails 4 development to run `:Rake` and avoid falling down to the deprecated `test:recent`.

This is related to Issue #252.