[DOC Beta] Remove duplicate actions documentation.

I should have done this as a part of https://github.com/emberjs/ember.js/pull/4846 but it didn't occur to me until this morning. 

Most of the `actions` documentation was duplicated in 2 places. It can be found in [ActionHandler](https://github.com/emberjs/ember.js/blob/master/packages/ember-runtime/lib/mixins/action_handler.js#L28-L146) and in the [Route](https://github.com/emberjs/ember.js/blob/70c7523b892ad42f3fa709f4cded6a66beb9162b/packages/ember-routing/lib/system/route.js#L302-L414). This duplication was needed previously to document some built in actions (`willTransition` and `error`) that are route specific and not found in other classes that mixin the `ActionHandler`. Pr #4846 documented these built in actions as `events` on the Route so we no longer need to call them out as a part of the `actions` docs.

This pr removes the `actions` docs in the `Route` so now it inherits the `ActionHandler`'s `actions` docs.

![screen shot 2014-05-20 at 10 10 17 am](https://cloud.githubusercontent.com/assets/54056/3028196/e47fd2ca-e029-11e3-8620-cb644d694d80.png)