Set permissions for BBB rooms and servers

[GoogleCodeExporter]

Restrict the access permissions for BBB rooms and servers. Currently everyone 
can access any room and manipulate the servers.

First thoughts on permissions:

- Anything server related can only be manipulated by the admin user

- Space's room:
  - Public spaces:
    - Rooms are public, can be joined by anyone.
    - If the user is a member of the space, he joins as moderator. If he's not a member (or is an anonymous user), he joins as a normal attendee.
    - Should never require a password.
  - Private spaces:
    - Rooms are private.
    - Can only be joined by members of the space. Everyone joins as moderator.
    - If a non space member (or anonymous user) tries to join, should ask for a password.

- User's room:
  - The owner joins as moderator, the others as attendees.
  - Rooms can be private or public:
    - Public: Anyone can join. Does not require a password.
    - Private: Require a password to join.

Original issue reported on code.google.com by leonardo...@gmail.com on 26 Apr 2011 at 2:47

[GoogleCodeExporter]

Original comment by fbot...@gmail.com on 5 May 2011 at 5:04

• Changed state: Started

[GoogleCodeExporter]

Finished. All changes make on application_controller.rb. Overriding 
bibluebutton_rails function:
- bigbluebutton_user
- bigbluebutton_role

Original comment by fbot...@gmail.com on 6 May 2011 at 5:50

• Changed state: Fixed