add globalize relation class that selectively modifies query conditions
to return results from translation table for translated attributes.
use user instead of post in tests where we need an untranslated attribute.
add tests to make sure we don't load translations unless there are translated attributes in the query conditions.
only reload translations if we've performed a find.
Merge pull request #274 from svenfuchs/rails4_globalize_relations

Handle translated attribute key/values in relation queries