Serialize

We do two big things in this PR to set the stage for creating the Data tab, which will list the models and collections.


#### Add Objects to Agent
1. We add Backbone and Marionette to the agent, `__agent.Backbone`, `__agent.Marionette`
2. We add the window's Backbone and Marionette to the agent: `__agent.windowBackbone`, `__agent.windowMarionette`

We need these objects so that we can properly serialize Model attributes. What do I mean, well the second part of the PR adds `__agent.serializeObject`. btw we stole this a big chunk of this from the **ember-inspector**.

The serialize method takes anything in and creates a fancy string representation of it:

some sample output
```
{ b: <Backbone.Model>, d: [Object] }
{ 0: <Marionette.CollectionView>, 1: foo }
```