FIX: Buffer overflow: Mode::timers

src/mode/Mode.h

@@ -127,7 +127,7 @@ private:
 
     void handleTimers() {
       milliseconds_t ms = millis();
-      for (Timer *timer = timers; timer < timers + sizeof(timers); timer++) {
+      for (Timer *timer = timers; timer < timers + countof(timers); timer++) {
         if (timer->interval > 0) {
           milliseconds_t milliseconds = ms - timer->last;
           if (milliseconds >= timer->interval) {

src/serial.cpp

@@ -25,6 +25,9 @@ void serial_loop() {
       case '9':
         setMode((ModeId) (input - '0'));
         break;
+      case 'a':
+        setMode((ModeId) (input - 'a'));
+        break;
       case '+':
         setBrightness(display.getBrightness() + 10);
         break;