Added quite a lot checks for admingroups save and load functions.
It should handle correctly all cases with even missing files to missing write or read permissions at filesystem.

fixed adding admin to group, since i did we do reload before adding, the reference to original group-object is missing.
Sometimes, when the file wasn't loaded from disk saving successed, othervice adding an admin to group failed, even a chat message was sent that it successed, now it has proper failure message too :)