Add Ember.on, Function.prototype.on, didInit event

This commit adds `Ember.on(eventName, func)` and `Function.prototype.on`
as cousins to `Ember.observes` and `Function.prototype.observes`. This
provides a declarative form of marking methods to execute when an event
fires.

This is useful for mixins which need to do things on `didInsertElement` and `willDestroyElement`, but don't want to force a call to `super` from the classes that include it:

    Ember.Mixin.create({
      doSomethingWithElement: function() {
        // Executes whenever the "didInsertElement" event fires, regardless of the presence of a method named `didInsertElement`
      }.on('didInsertElement')
    });

In addition, this commit also makes Ember.Object send a `didInit` event after initializing. This provides for an elegant solution to a common need: marking a function as an observer and also executing it at creation time. e.g.

    Ember.Object.extend({
      upateOptions: function(){
        var opts = this.get('controller.foo').importantTransform();
        this.set('options', opts);
      }.observes('controller.foo').on('didInit')
    });
Merge pull request #3155 from lukemelia/ember-on

Add Ember.on, Function.prototype.on, and didInit event
don't alter shape of meta object in ctor

thanks @eviltrout and @ebryn
Update LICENSE
Use a single array for actions.

Eliminate array creation for each listener added.
Fix Ember._suspendListeners

We need more tests around this code.
update s3 upload task and update Gemfile.lock dependencies

Stops the error of "ember.prod.prod.js" not found on Travis, and also
updates the Gemfile to use the new gzip stuff for uploading to s3.
Merge pull request #3164 from fivetanley/new-s3-config

update s3 upload task and update Gemfile.lock dependencies