@brief Method is used to add @see ZoneListener "ZoneListener" class element
which will notify entering or leaving @see Zone "Zone"s.
@note Do not forget to remove listener if it is no longer needed!
@param listener Сorresponding @see ZoneListener "ZoneListener" class.
@brief Method is used for removing previously added @see ZoneListener "ZoneListener" class element.
@param listener Сorresponding @see ZoneListener "ZoneListener" class to remove.