add missing property getter for "Hold Last Look"

protocol/sacn/receiver.cpp

@@ -67,6 +67,16 @@ void Receiver::setHoldLastLook(const bool state)
 }
 
 
+/**
+ * @brief Receiver::isEnabledHoldLastLook
+ * @return
+ */
+bool Receiver::isEnabledHoldLastLook() const
+{
+    return HoldLastLook;
+}
+
+
 /**
  * @brief Receiver::subscribe
  * @param num

protocol/sacn/receiver.h

@@ -69,6 +69,7 @@ public:
   ~Receiver();
 
   void setHoldLastLook(const bool);
+  bool isEnabledHoldLastLook() const;
 
   virtual void subscribe(const uint16_t);
   virtual void unsubscribe(const uint16_t);