Function empty

include/cinder/Function.h:76–76

	void	unregisterCb( CallbackId cbId ) { mCallbacks.erase( find( cbId ) ); }
	
	bool	empty() const { return mCallbacks.empty(); }

	iterator find( CallbackId cbId ) { for( iterator it = begin(); it != end(); ++it ) if( it->first == cbId ) return it; return mCallbacks.end(); }
	iterator begin() { return mCallbacks.begin(); }