Fixing multi-word automatic inverse detection.

Currently, ActiveRecord models with multiple words cannot have their inverse associations detected automatically. Thus, class names like "MixedCaseMonkey" on AR models will not get their inverses found correctly. The proposed patch should change that.

In the test that has been added, both the `MixedCaseMonkey` and the `Man` models should have inverses defined on their associations. However, only the inverse association on `Man` is found correctly.

\cc @spastorino