Fix regression with tile 10 not having nothing behind it

This broke when I was refactoring things earlier, because we no longer
have a direct reference to the contents array, instead using a copied
int. But we have a settile() function anyway, so why not use it?

desktop_version/src/Map.cpp

@@ -2057,7 +2057,7 @@ void mapclass::loadlevel(int rx, int ry)
                 //Breakable blocks
                 if (tile == 10)
                 {
-                    tile = 0;
+                    settile(i, j, 0);
                     obj.createentity(i * 8, j * 8, 4);
                 }
                 //Directional blocks