resolved some todos

FlippR-Driver/include/output/items/Lamp.h

@@ -10,6 +10,8 @@
 
 #include "Item.h"
 
+#include <chrono>
+
 namespace flippR_driver
 {
 namespace output
@@ -25,6 +27,7 @@ public:
   virtual void activate() = 0;
   virtual void deactivate() = 0;
   virtual bool is_activated() = 0;
+  virtual std::chrono::milliseconds get_activation_time() const = 0;
 };
 
 }