Multiple fixes

- increase WLED_MAX_BUSSES for C3 (fixes #4215)
- fix for #4228
- fix for very long running effect (strip.now, strip.timebase)
- C++ API change to allow `seg.setColor().setOpacity()`

usermods/stairway_wipe_basic/stairway-wipe-usermod-v2.h

@@ -96,7 +96,7 @@ void setup() {
     jsonTransitionOnce = true;
     strip.setTransition(0); //no transition
     effectCurrent = FX_MODE_COLOR_WIPE;
-    resetTimebase(); //make sure wipe starts from beginning
+    strip.resetTimebase(); //make sure wipe starts from beginning
 
     //set wipe direction
     Segment& seg = strip.getSegment(0);

usermods/stairway_wipe_basic/wled06_usermod.ino

@@ -86,7 +86,7 @@ void startWipe()
   bri = briLast; //turn on
   transitionDelayTemp = 0; //no transition
   effectCurrent = FX_MODE_COLOR_WIPE;
-  resetTimebase(); //make sure wipe starts from beginning
+  strip.resetTimebase(); //make sure wipe starts from beginning
 
   //set wipe direction
   Segment& seg = strip.getSegment(0);