Access tab

I'll let you guys review and comment on this first instead of just merging it in as it's a bit bigger addition than most of what I've done lately. You'll need to either reinstall or manually hide fields manage_access, view_groups and edit_groups from the edit view for this to work properly (saving wont work if the fields are there twice, obviously).

So no more of the original fields visible nor the access info. Access tab is shown only if the user has user-admin permission.

I decided to implement this using AngularJS as it seemed like a perfect fit for the job (and it was fun ;). The ng part is in its own template file for convenience. Angular's JS file is loaded from CDN atm - probably it should be brought in (or should we use that AngularJS module of yours Antti?).

This implements #11 and also #21 (option b) as when the page starts managing its own access, the inherited values are there as a starting point.