## About The Pull Request
[Implements a new cardinal only bitmask smoothing
mode](d565564918)
The icon cutter supports generating cardinal only dmis, we should
support using them.
This is fairly trivial, just involves skipping a step to handle
diagonals.
While I'm here, makes adding new smoothing modes easier by creating a
"using smoothing" group define
[Removes undef for smoothing
junctions](4c0a4d6e34)
It is useful to be able to reference these in the general codebase, they
should not be considered scoped to just icon smoothing
[Fixes a copypasta issue breaking burn states for asteroid
snow](a41b31dbe2)
[Removes SMOOTH_BROKEN_TURF and
SMOOTH_BURNT_TURF](8a9a340728)
Bitflags should not be this specific, this should be a var on
/turf/open, so that's what I'm making it.
## Why It's Good For The Game
Upstreams a bit of wallening work, cleans up the codebase some
## Changelog
🆑
fix: Some varieties of snow now visually melt properly again when burned
/🆑
7d1e9e1c0a