added updateGroup functions to gxs services.



git-svn-id: http://svn.code.sf.net/p/retroshare/code/trunk@7101 b45a01b8-16f6-495d-af2f-9b41ad6348cc
Improved GxsGroupDialog for Show / Edit of Groups.
 - Added Show/Edit Menu Options for all services.
 - Fixed up BUTTONBOX_OK bugs.
 - Tested name changes for all services.



git-svn-id: http://svn.code.sf.net/p/retroshare/code/trunk@7102 b45a01b8-16f6-495d-af2f-9b41ad6348cc