Notaði fyrrum p_controller og bætti við virtual pi_controller

include/controller.h

@@ -0,0 +1,18 @@
+#ifndef CONTROLLER_H
+#define CONTROLLER_H
+
+class Controller
+{
+public:
+    virtual ~Controller()
+    {
+    }
+
+    virtual double update(double ref, double actual) = 0;
+
+    virtual void reset()
+    {
+    }
+};
+
+#endif