Don't need to specify FactoryGirl inside its config
added test case for 4 people
added ByPreviousGroupScorer to GroupSelector
Whoops forgot to delete the duplicated method
Add support for 4 person groups to ByGenderScorer
Fix two bugs in ScoreTransformer.score_distances

1. Equally scored distances did not work at all.
2. the min score was always bumped up.