Indicate what special roomnames are in the levels

This just adds booleans roomname_special to the level classes in
preparation for the localization system to use them.

This commit is part of rewritten history of the localization branch.
The original (unsquashed) commit history can be found here:
https://github.com/Dav999-v/VVVVVV/tree/localization-orig

desktop_version/src/Otherlevel.h

@@ -7,6 +7,7 @@ public:
     const short* loadlevel(int rx, int ry);
 
     const char* roomname;
+    bool roomname_special;
     const char* hiddenname;
 
     int roomtileset;