Fix components inside group helper

Components (like `link-to`) end up with the wrong context when used
inside a `#group` helper. And their templates don't get grouped.

I understand that #group is experimental, but as long as the support for
it remains in master, it makes sense to not leave it broken.
Merge pull request #4957 from ef4/grouped-component

Fix components inside group helper
[BUGFIX beta] Route#modelFor shouldn't rely on router

This is especially useful for unit testing. In cases where
there is no router, `modelFor` will no longer cause an exception.
use ember-cli as the CLI to build ember. (broccoli under the hood)

Such dog-fooding.

bonus, ember-cli now comes with  broccoli-sane-watcher, which dramatically reduces the cost of file system watching.

Enjoy your battery life!
Merge pull request #4982 from stefanpenner/ember-cli

use ember-cli as the CLI to build ember. (broccoli under the hood)
Cleanup ember-cli transition.
Use qunit-phantom-runner from bower.
Merge pull request #4983 from rjackson/fixes-for-ember-cli-usage

Build system cleanup.
Initial update to Handlebars 2.0.