This function sends dimming commands (using Switch Multilevel Command Class) to devices in association group defined as ZUNO_ASSOCIATION_GROUP_SET_VALUE_AND_DIM (see ZUNO_SETUP_ASSOCIATIONS).
zunoSendToGroupDimmingCommand(CTRL_GROUP_n, direction, start_stop)
number of group: CTRL_GROUP_1, ... CTRL_GROUP_5
FALSE for dimmig up, TRUE for dimming down
TRUE to start diming, FALSE to stop dmming
zunoSendToGroupDimmingCommand(CTRL_GROUP_2, FALSE, TRUE); // start dimming up