Even more slope-related fixes
What it says on the tin pretty much:
Currently included fixes:
* Pusher specials applied to FOFs did not properly account for slopes applied to the bottom plane; this probably was just a minor slipup that appeared on adding the support in the first place, I take it? (some waterfall in the last section of SUGOI's Fudge Canyon is the only place I can think of offhand where this bug is noticable)
See merge request !114
If there's any reason to bring the old system back we could make it togglable by one of the linedef flags I suppose. Not that many people would actually use it though, most likely
for some apparent reason the compiler didn't like the while loop condition edit on its own (it complained about inline failures for P_MobjReadyToTrigger for some reason), so I had to add that extra bit above the while loop... and it was happy again, huh
Two interesting points of note:
* The touchspecial sector flag seems to actually do its job now.
* Detection of sectors with polyobjects in seems to have done this incorrectly, but this doesn't mess with anything about touching the polies themselves so it seems to really only handle edge cases where the polyobject was too close to the border of another sector (which would've likely made rendering glitches anyways).
* There was a whole swathe of teetering code that was basically never run properly because of this mistake. I did a simple fix at first, but you started teetering whenever you were slightly less than your radius away from a sector's edge, which was completely different and undesirable behaviour. Instead, I cut out the code that was never running, and just left the hacky method in instead since it was more accurate to what we want in general.
* Only change texture when stationary or moving down, for additional fidelity to source material. This has zero overhead, and actually might REDUCE lag in some circumstances... my nitpickiness wins again.
* Apply ML_EFFECT1 to it to make it invisible and intangible (removing (FF_SOLID|FF_RENDERALL|FF_CUTLEVEL) from it) from every side except the bottom. Becomes visible and tangible when it's hit once. Might fuck over players in mp, but really our Mario blocks are so high in the air (and we'd need to update Pipe Towers to take advantage anyways) that they're super unlikely to get a kill this way
* Checks for the Brick Block have been switched over to the presence of FF_SHATTERBOTTOM instead of checking for the source linedef's flags every time.
Linedef type 4 now works as follows.
* Frontside x offset is dash speed.
* Effect 4 flag doesn't center the player. (same as before)
* Effect 5 flag sends them off in rolling frames. (as a result there is only one speed pad sector type now, not two)
* Frontside upper texture is sound to play on launch, defaults to sfx_spdpad when not given
