Added UDP multicast for plugin discovery (#153)

* Added Timer

* Added UDPSocket::GetAddr

* Added MessageHandlers::SendBeacon()

* PoC of starting a timer on PluginEnable

* C++11

* Added Timer to xcode project

* C++11 in cmake

* added Timer to cmake

* use function pointer in Timer

* moved Timer to namespace

+ wait for thread to join when stopping the timer

* Windows: changed uint to unisgned short

* Windows: Added Timer.h/cpp to project

* GetAddr static

* Send xplane and plugin version with BECN

* SendBeacon with params

* fixed file copyrights

* Include functional

to fix Linux compile error

* review fixes

* Send plugin receive port in BECN

* review fixes

xpcPlugin/MessageHandlers.h

@@ -38,6 +38,8 @@ namespace XPC
 
 		/// Sets the socket that message handlers use to send responses.
 		static void SetSocket(UDPSocket* socket);
+        
+        static void SendBeacon(const std::string& pluginVersion, unsigned short pluginReceivePort, int xplaneVersion);
 
 	private:
 		// One handler per message type. Message types are descripbed on the