chore(mocks): Move MockHttpBackend into angular.mocks and update http_spec to use the new syntax
feat(directives): ng-class, ng-class-odd, ng-class-even

Closes #120
chore: updated pubspec.lock
chore(ng_events): don't explicitly pass default parameters
fix(test): re-include excluded tests
chore(pert): added callable object pert test
chore(NgAnnotations): Added reasonable defaults if missing
chore(warning): removed dart analyzer warning