(svn r9898) -Fix (r9874): Many...

- Group protection status wasn't changed via a command.
 - Group renaming didn't check group owner (and in fact changed the owner,
   just like renaming a sign...).
 - Added owner checks to other group commands.
 - Invalidate window data after the command has been completed instead of after
   the command has been sent. This fixes gui issues in network play.

src/command.h

@@ -149,6 +149,7 @@ enum {
 	CMD_ADD_VEHICLE_GROUP            = 123,
 	CMD_ADD_SHARED_VEHICLE_GROUP     = 124,
 	CMD_REMOVE_ALL_VEHICLES_GROUP    = 125,
+	CMD_SET_GROUP_REPLACE_PROTECTION = 126,
 };
 
 enum {