Change all tilemaps to be short[1200] instead of int[1200]

This removes around megabyte from the binary, so a stripped -Og binary
went from 4.0 megabytes to 2.9 megabytes, and an unstripped -O0 binary
went from 8.1 megabytes to 7.1 megabytes, which means I can now finally
upload an unstripped -O0 binary to Discord without having to give money
to Discord for their dumb Nitro thing or whatever.

desktop_version/src/Map.h

@@ -88,7 +88,7 @@ public:
     int roomdeaths[20 * 20];
     int roomdeathsfinal[20 * 20];
     static const int areamap[20 * 20];
-    int contents[40 * 30];
+    short contents[40 * 30];
     bool explored[20 * 20];
     int vmult[30];