implemented Clrwdt Instruction (#34)

Co-authored-by: Darkress <30271678+DarkressX@users.noreply.github.com>
Reviewed-on: darkress/pic16f84-sim#34

de/darkress/pic16f84sim/commands/Clrwdt.java

@@ -0,0 +1,24 @@
+package de.darkress.pic16f84sim.commands;
+
+import de.darkress.pic16f84sim.microcontroller.*;
+
+public class Clrwdt extends LiteralCommandUtils implements Command
+{
+
+    public Clrwdt()
+    {
+    }
+
+    @Override
+    public void execute()
+    {
+        ProgramCounter.incPC();
+        Cycles.incCycles();
+
+        Memory.setRegister(0x03, Memory.getRegister(0x03) | 0x18);
+        if(Timer.getPrescalerAssignment()) {
+            Timer.resetTimeToTimerIncrease();
+            Watchdog.resetWatchdogTimer();
+        }
+    }
+}