switch reviewers app history to use comm api (bug 920746)

**Context:**

- The Reviewer Tools review pages for individual apps have a review history table that details previous review actions, reviewer comments, and attachments by version.
- When reviewing/commenting/attaching a file, an ```ActivityLog``` object is created.
- We have a command to migrate review history/comments/attachments from ```ActivityLog``` to ```Commbadge``` objects (which feature an API)

**Solution:**

- We change the review history table to query the Commbadge Threads/Notes/Attachments APIs via JS, trying to keep everything looking the same.
- We keep this under a ```waffle```, so when the waffle is off, we use the template that queries ```ActivityLog``` objects.
- If we ever flip the switch, we need to make sure all the objects are migrated. We can run the migration command, but then any incoming reviewer actions will also need to be migrated. Thus, we must be creating Commbadge Threads/Notes/Attachments alongside ActivityLog objects in the reviewer utils

**Notes:**

- It's a big patch, but since commbadge is flipped on on -dev, it may be easier to do everything in one fell swoop.
- Depends on https://github.com/mozilla/zamboni/pull/1629 for the attachment creation utility.

**Screenshot:**

![screen shot 2014-01-08 at 6 39 35 pm](https://f.cloud.github.com/assets/674727/1874645/4a98a862-78d7-11e3-964f-10e04a2bc198.png)