Images can now replicate to groups.  Next to add is group joining similar to how hosts can get groups.

git-svn-id: https://svn.code.sf.net/p/freeghost/code/trunk@2514 71f96598-fa45-0410-b640-bcd6f8691b32
Merge svn with dev-branch
Merge master with svn
Merge master with dev-branch