Allow users more albums permissions flexibility

[Song0330]

Several requests go under this:

1. Allow users to subscribe to groups

2. Allow users to create and manage their own groups

3. Allow users to set privacy permissions on albums by users, in addition to or instead of setting permissions by groups

I'd love for my users to be able to easily control who can see their albums without waiting for an admin to create custom groups.

[sharkey]

This would be perferct.  I have a friend who only wants her family and friends to see her pics, not every registered user.  I made her her own group but it would be better if other users can do that without e-mailing me.