It turns out that it will be useful to allow the get_js_*_data for

actions to have access to the rendering context. This change does that

by introducing some new template tags that call the methods with the

context.
This also allows improving the implementation of the menu view a bit,

removing non-rendering actions from the data sent to the JS model,

preventing some warnings about unknown IDs from popping up in the case

that an extension has hidden a menu-item action.

Implemented a custom action that used the context parameter.
Used HideActionHook to hide a menu item action and saw that I was no

  longer getting warnings in the JS console.
Ran js-tests.