Fix crate math.

I forgot that -1 & 1 = 1 rather than 0 so all the bit math didn't work. But I can fix it with polynomial algebra! this is much better.

chameleonic.p8

@@ -502,11 +502,7 @@ function level:get_latch(dx,dy,px,py)
  local dx1,dy1=-sgn0(dx),-sgn0(dy)
 
  if crate then
-  if crate.def & (
-    dy1 >>> 15 | 
-    (dy1 & 0x1) << 2 |
-    (dx1 & 0x8000) >>> 12 |
-    (dx1 & 0x1) << 1) ~= 0 then
+  if crate.def & dy1*dy1*(2.5+1.5*dy1)+dx1*dx1*(5-3*dx1) ~= 0 then
    return {
     el="crate",
     dx=dx1,dy=dy1,