Use insert_aliased_from_fixturize when inserting ivars
version bump
* Add Fixturize.enabled flag to turn on/off Fixturize in tests (off by default)
* Make methods private
* spec helper: use the same collection for MongoMapper.database['users_for_fixturize'] and User (MongoMapper::Document)
* Rename instrument_database => _instrument_database (it must be public)
version bump to 0.1.4