OpenGL slope fixes again
This branch just adds the relevant code for OpenGL to properly check slopes regarding "closed door" segs (those between two sectors that cannot be crossed normally) and "window" segs (those between two sectors of differing plane heights that you CAN cross, which would probably display top or bottom textures), so you don't get HOMs when the the slopes create a closed door even though the normal sector heights wouldn't or something.
(if you couldn't understand that, my slopes test map shows what I mean to the right of the player start: https://dl.dropboxusercontent.com/u/25409000/2.1/mi-slopetest.wad)
See merge request !81
Linedef type 14 (Bustable block parameter)
* Applied to one of the linedefs of any FOF's control sector
* Concatenation of frontside textures is MT_ object type to spawn, defaults to MT_ROCKCRUMBLE1 if not present
* Sound played when being busted is object type's activesound
* Frontside x offset is spacing (in fracunits) of spawned particles, defaults to 32<<FRACBITS
* Frontside y offset is the fuse of spawned particles in tics, defaults to 3*TICRATE, if set to -1 assume infinite lifetime
* Effect 1/Slope Skew flag makes particles fly out
Linedef type 250 (Mario Block):
* No Climb flag turns it into a brick block (busts when hit from the bottom, player hits their head/fist/whatever, no more upwards momentum)
* Actively impede your acceleration
* Make your animation speeds faster whenever you're moving (to give off that Looney Tunes effect)
The former change is something that was present in the few low-friction circumstances in the classics, and makes low-friction surfaces more of an active challenge. The latter change is just something I did for fun to more clearly communicate that things are different with the physics here.
High friction surfaces DO NOT involve any of this, since it ended up basically cheesing their existing gameplay.
*Friction linedef effect is now -
1) controlled by x offset instead of length - offset of -100 is maximum iciness, offset of +483(!!!) is the maximum sludginess BUT things are scaled such that +100 is about the maximum sludginess any reasonable human being would want in a level, 0 is ORIG_FRICTION)
2) not reliant on a sector special to function (can be applied solely by tag to in-map sectors or solid FOF control sectors)
Basically this makes sure numwadfiles is updated before loading the SOC/Lua scripts, so if a Lua script calls COM_BufInsertText with the contents "addfile scr_mysticrealm.wad" it can't overwrite the last written wadfile slot! Not that COM_BufInsertText really should be used like that to begin with
*Didn't take into account object scale
*Doubled force when on the ground (ignore what the comment of the line I moved says, it was relevant for slopes...)
This also led to a mistake with slopes, where I was double-multiplying by the gravity constant to get half (because of a quirk of numbers...)
