Fix examples in action helper docs.

As pointed out by @michaelBenin in
https://github.com/emberjs/website/issues/956.
Removed ridiculously dated idiom from container views docs

Mmm, binding current view to the singleton `App.appController`.
Merge pull request #3497 from rjackson/fix_action_docs

Fix examples in action helper docs.
Merge pull request #3498 from machty/old-container-view-nonsense

Removed ridiculously dated idiom from container views docs