add initializers to marionette module

init.js

// v0.9.0 of Marionettte will strip down the Modules to bare minimums, removing
// the ability to add initializers. you can re-add them to your module, as-needed,
// by doing this:

MyApp.module("Foo", function(Foo, MyApp, Backbone, Marionette){
  var initCallbacks = new Marionette.Callbacks();

  Foo.addInitializer = function(initializer){
    initCallbacks.add(initializer);
  }

  Foo.start = function(options){
    initCallbacks.run(options, Foo);
  }
});