Fix broken ActionHook code

Review Request #2069 — Created Jan. 26, 2011 and submitted

Information

Review Board
extensions

Reviewers

The ActionHook code was way out of date, and buggy.  The djblets_misc tag library, for example, doesn't exist anymore.

Gave it a bit of love.  Seems to work better now - adds the appropriate links to review requests at least.
Ran an extension using the ReviewRequestActionHook.  Had the link show up in the review details pane just fine.

Didn't test with images.