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/xpcPlugin/xpcPlugin.vcxproj

@@ -206,6 +206,7 @@
     <ClInclude Include="..\Log.h" />
     <ClInclude Include="..\Message.h" />
     <ClInclude Include="..\MessageHandlers.h" />
+    <ClCompile Include="..\Timer.h" />
     <ClInclude Include="..\UDPSocket.h" />
   </ItemGroup>
   <ItemGroup>
@@ -214,6 +215,7 @@
     <ClCompile Include="..\Log.cpp" />
     <ClCompile Include="..\Message.cpp" />
     <ClCompile Include="..\MessageHandlers.cpp" />
+    <ClCompile Include="..\Timer.cpp" />
     <ClCompile Include="..\UDPSocket.cpp" />
     <ClCompile Include="..\XPCPlugin.cpp" />
   </ItemGroup>