Smart xswiftbus compatibility check based on git commit SHA-1

This is more tolerant that the simple check based on version numbers.
Different versions can be compatible if they have the same SHA-1 when
considering only those files that can influence xswiftbus.

src/plugins/simulator/xplane/xswiftbusserviceproxy.h

@@ -100,6 +100,9 @@ namespace BlackSimPlugin
             //! Get XSwiftBus version number
             QString getVersionNumber();
 
+            //! Get SHA1 of the last commit that could influence xswiftbus
+            QString getCommitHash();
+
             //! Get own aircraft situation data
             void getOwnAircraftSituationDataAsync(BlackSimPlugin::XPlane::XPlaneData *o_xplaneData);