Remove debug prints, correct reverse gear, tidy loop

- Comment out all Serial debugging statements and the artificial delay
  in
  Engine::update.
- Change reverse gear detection from `gearIdx == 5` to `gearIdx == -1`.
- Simplify the main loop in Projekt.ino by removing unnecessary braces,
  eliminating temporary blink variables, and calling
  `display.updateDirection`
  directly with the pin reads.

Projekt.ino

@@ -30,13 +30,12 @@ void setup() {
 }
 
 void loop() {
-  if (gear.update()) {
+  if (gear.update())
     display.updateGear(gear.getGearChar());
-  }
 
-  leftBlink = digitalRead(TS_LEFT);
-  rightBlink = digitalRead(TS_RIGHT);
-  display.updateDirection(leftBlink, rightBlink);
+  display.updateDirection(
+    digitalRead(TS_LEFT),
+    digitalRead(TS_RIGHT));
 
   unsigned long now = millis();
   float dt = (now - prevUpdate) / 1000.0f;