Added StencilColor to Set/GetActorProperty
- the ACS functions GetSectorFloorZ and GetSectorCeilingZ now interpret tag=0 as 'any sector' and return the z height of whatever sector is at those coordinates.
Enable fighting between different types of gargoyles and golems

In vanilla Heretic:
- Gargoyles are able to fight with Fire Gargoyles
- Golems are able to fight with Nitro Golems, both regular and ghosted versions
Remove garbage characters from info CCMD
Missed space in flags7 line.
Merge branch 'master' of https://github.com/crimsondusk/zdoom
Merge branch 'upstream2' of https://github.com/Edward850/zdoom
Merge branch 'upstream' of https://github.com/Edward850/zdoom
fixed: APROP_StencilColor was not implemented for CheckActorProperty.
Merge branch 'getsectorz_take2' of https://github.com/crimsondusk/zdoom
Fixed prediction thinglist order restoration

Prediction didn't take sector_thinglist and thinglist order into
account.
This notably broke the order in which things were damaged.
Cleanup old prediction fix development code
Don't compile some unused DUMB tables spotted by Clang
Fixed: DSMF loader wrote outside filename array's bounds
Change , to && in 2 for loops in Oktalyzer loader

- For something like i < n_chnnels, j < 4 , the first condition is completely unused, so why put it in the for loop at all? I assume these are supposed to be binary-and and not sequences.
Upgrade game-music-emu to version 0.6.0
Use flexible array members for structs that end with var-sized arrays

- Since Clang++, G++, and VC++ all support this extension (even though it's
  technically officially only part of C99), use it. It lets Clang's array-
  bounds checker know that these are meant to be accessed out of their so-called
  "bounds".
Disable warning C4200 on VC++

- This warning is about using zero-sized arrays in structs (aka flexible
  member arrays). It's standard-enough for our purposes, so don't warn
  about it, since neither GCC nor Clang do.
Redo GME warning-silencing that was undone by commit fbddfbe57
Add new GME files to VC++ 2005 project