Limit of the nested groups

[nerolapis]

Create something like

- (SFPSDGroupOpeningLayer *)openGroupLayerWithName:(NSString *)name andOpacity:(float)opacity andIsOpened:(BOOL)isOpened andError:(NSError **)error

and

- (SFPSDGroupOpeningLayer *)openGroupLayerWithName:(NSString *)name andError:(NSError **)error

in order to handle the limit of the nested groups (10 levels of nesting).