changes:
* damage dealing code expects the default actor to not have Death state. workarounded with a dirty hack.
* added Weapon DECORATE properties: `Weapon.PlayerSpeedScale walk [run]`, `Weapon.PlayerJumpScale scl`, and `DisablePlayerRun` flag
* added DECORATE actions: `A_PlayerWeaponSpeedScale(walk, [run])`, `A_PlayerWeaponJumpScale(scl)`, `A_PlayerWeaponDisableRun(flag)
* added DECORATE functions: `GetPlayerWeaponSpeedScaleWalk()`, `GetPlayerWeaponSpeedScaleRun()`, `GetPlayerWeaponGetDisableRun()`, `GetPlayerWeaponJumpScale()`
* fixed (i hope) the long-standing bug that caused occacional bad clipping; it is harmless, the engine simply rendered more linedefs than necessary
* new t-junction fixer (Space Ants eliminator); all rendering modes should have no Space Ants anymore (at least when there are no 3d floors)
* added DECORATE function `IsPlayerRunning()` (checks if run button is pressed, and the player is moving fast enough)
* implemented `CHF_DONTIDLE` DECORATE flag for `A_Chase()`
* fixed some bugs in lightmapped renderer (needlessly strict asserts ;-)
* minimap can show "blocking things" (it is a kind of cheating, but meh...)
* added option to clamp minimum light level for Doom (Vanilla-like) lighting (might help with ZDoom maps)
* implemented LOD levels for voxel models (turned on by default); this can significantly improve FPS with monster voxel packs
* completely reworked out-of-water jump code: it should really perform jumps now ;-)
* implemented experimental corpse sliding, to avoid "hanging corpses" effect (pickup drops will slide too)
* implemented more flags for `A_Explode()` DECORATE action (some new flags from recent GZDoom)
* fixes in `DoChase()` (leave `bInChase` flag set only if we branched)
* slightly faster DECORATE runtime label jumps (most jump targets are cached instead of re-evaluating them each time)
* fixed VERY NASTY bug in compiler; everything worked by sheer luck before (MANY-MANY THANKS to TDRR for help and patience!)
* hitscan missiles should activate lines as `LineAttack()` does (thanks, Steinkrauz!)
* fixed crash on maps with 3d polyobjects
