Update to Ember 1.8.1.

This was branched off #307 (so that I could start with a passing test suite).

* Inject `config` into controllers.
* Avoid deprecations from globals in template.
* Use container to lookup views (instead of globals).
* No need to advanceReadiness (automatic with visit now).
* Metamorph tags are no longer added, reducing the number of children.
* Use alias when appropriate.
* Remove extra nesting level in integration test.
* Remove view.state checks (in favor of _state).
* Keep elements fully within a single element.
* {{if}} is implemented as an Ember.View (without an element), and children
* must be valid DOM.
* Do not use globals to lookup views from template.
* Do not run timers in testing.
* Update to Ember 1.8.1.
* Controller#content -> Controller#model.
* Use standard Ember.Handlebars.registerBoundHelper.
* No need for the custom Ember.registerBoundHelper implementation.