Added Effect::start() and Effect::stop() to allow effects to reserve memory on start and free it afterwards.

include/Effect.h

@@ -16,6 +16,8 @@ class Effect {
     void setWindow(Window win) {
       window = win;
     };
+    virtual void start() {}
+    virtual void stop() {}
 };
 
 #endif

include/effect_cycle.h

@@ -10,6 +10,8 @@ class CycleEffect : public Effect {
     unsigned long effectSince = 0;
   public:
     void changeEffect();
+    void start();
+    void stop();
 
     boolean can_be_shown_with_clock();
     boolean clock_as_mask();