Set Secret Lab/Super Gravitron hidden names

It seems appropriate that these rooms should have their names shown on
the map screen.

desktop_version/src/Otherlevel.h

@@ -9,6 +9,7 @@ public:
     const short* loadlevel(int rx, int ry);
 
     std::string roomname;
+    std::string hiddenname;
 
     int roomtileset;
 };