Fix brocken Backbone.Model tests
Update overridables section in documentation
Remove route-related stuff from test-bb/env
Require underscore dep >=1.5.0 (as in bb 1.1.2)
Add missing end-of-file line-break
Remove test-bb/chain test -chain not part of 1.1.2
Test against underscore 1.7.0.
Add test-bb/model tests to node-version testrunner