(svn r1415) Move TILE_FROM_XY and TILE_XY to map.h and push TILE_[XY] bits from map.h into map.c.

Now the whole source except map.c is independent of TILE_[XY]_BITS!

map.c

@@ -2,6 +2,9 @@
 #include "ttd.h"
 #include "map.h"
 
+#define TILE_X_BITS 8
+#define TILE_Y_BITS 8
+
 uint _map_log_x = TILE_X_BITS;
 uint _map_log_y = TILE_Y_BITS;