add ACTION_DEFAULT_LAYER_TOGGLE to toggle a default layer on/off
#define ACTION_LAYER_TAP(layer, key) (ACT_LAYER_TAP<<12 | (layer)<<8 | (key))
/* Default Layer */
#define ACTION_DEFAULT_LAYER_SET(layer) ACTION_DEFAULT_LAYER_BIT_SET((layer)/4, 1<<((layer)%4))
+#define ACTION_DEFAULT_LAYER_TOGGLE(layer) ACTION_DEFAULT_LAYER_BIT_XOR((layer)/4, 1<<((layer)%4))
/* Layer Operation */
#define ACTION_LAYER_CLEAR(on) ACTION_LAYER_BIT_AND(0, 0, (on))
#define ACTION_LAYER_MOMENTARY(layer) ACTION_LAYER_ON_OFF(layer)