Feature discussion board ucla

This feature branch adds 4 features to the discussion boards.

1. You can now restrict discussion boards to course groups, there is a new ACL entry for each board in communities linked to courses, run the migration page at www-root/admin/communities?section=migrate, this will convert the boards.

2. You can now group boards into categories and have them accordion together, it uses jQuery UI. If no categories are added then the boards will act as they did in the past.

3.  You can now upload files to the discussion boards, the permissions on the storage folder might need to be changed, www-root/admin/communities?section=migrate will let you know if it needs to be changed.

4. Profile photos are added to the view-post page, if the user as privacy level 1 then the photo isn't shown to regular users, just to Admins and themselves. 
![screen_shot_2014-06-06_at_1_00_35_pm](https://cloud.githubusercontent.com/assets/3229695/3205361/6e36e1dc-edb5-11e3-8f95-f77ac4110185.png)