ui, logic: design for license ui and forcing the user to enter a key on first open

This change integrates the license key ui into the application and makes it necessary for the user to enter a correct
key. The check for a correct key is done on startup and whenever a project is loaded. The check for the key also
includes a check whether the location of the application has changed.

cmake/PublicKey.h.in

@@ -1,10 +1,10 @@
 #ifndef PUBLIC_KEY_H
 #define PUBLIC_KEY_H
 
-// This File(PublicKey.h) is generated with CMake 
+// This File(PublicKey.h) is generated with CMake
 
 #include <string>
 
 static const std::string PublicKey = "@KEY@";
 
-#endif //PUBLIC_KEY_H
+#endif // PUBLIC_KEY_H