Effect swirl is now shown with clock.

src/effect_twirl.cpp

@@ -1,6 +1,9 @@
 #include "effect_twirl.h"
 #include "functions.h"
 
+boolean TwirlEffect::can_be_shown_with_clock() { return true; };
+boolean TwirlEffect::clock_as_mask() { return true; };
+
 void TwirlEffect::loop() {
 	double center_x = _real_center_x; // - (cos8(_center_offset_angle)>>6);
     double center_y = _real_center_y; // + (sin8(_center_offset_angle)>>6);