Changes to support Backbone 0.9

[trevorquinn]

Couple changes:

• Changed reference to private Backbone method from _performValidation to
  _validate to match Backbone 0.9
• Also updated qunit references from "equals" to "equal" to avoid deprecation errors in the unit test

Problem is, Backbone 0.9 won't allow invalid models to be created, which means you can't create empty models with required attributes. So most of the unit tests will still fail. The master version of Backbone removes this model creation restriction, so hopefully a future release of Backbone won't have it.

[nealstewart]

Hey man. Thanks a lot for doing this! I've been really busy and not doing much client-side code, so I haven't had to scratch the validation itch in a while. I'll take a look over this tomorrow and probably pull 'er in!

[trevorquinn]

Okay, so Backbone 0.9.1 does allow invalid models to be created (unlike 0.9.0), because silent:true is checked inside the Backbone _validate function. If found, the Backbone validate function is not called. So I needed to copy that silent:true check into the backbone.validations newPerformValidation function. All unit tests now pass.