Wrong obstacles with diagonal dynamic tiles

Created by: christopho

Dynamic tiles whose ground is a diagonal wall don't behave as expected, unless their size is 8x8. For example, a tile of size 16x16 with a diagonal top-right wall actually results in four diagonal obstacles of size 8x8, which is wrong. We obtain

\\
\\

instead of what we have with a static tile:

\X
 \

Furthermore, diagonal walls only work if they are aligned on the grid. With dynamic tiles, this assumption is no longer always true.