From cf5349dca4d6dd0f257ba637870fff46cf400aba Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas Backbone.Collection
"sort" comparator functions take two models, and return -1 if
the first model should come before the second, 0 if they are of
the same rank and 1 if the first model should come after.
+ Note that Backbone depends on the arity of your comparator function to
+ determine between the two styles, so be careful if your comparator function
+ is bound.