* support for SSI container format - this is an obscure format used by a few Duke Nukem mods - added to have this subsystem identical between both engines.
* removed some dead wrapper code
* made the Open methods local to their implementations, this was never called virtually.
* new texture format: ANM - this reads the first frame of a Build-ANM movie as a texture.
* some preparations for indexed (paletted) rendering.
* optimization of the patch texture checker - do not read in the entire file if checking the initial header is sufficient for rejecting it.
* removed refreshFreq variable and related code. This only got into the backend because of stupid interpolation code in some of the Build games which has long been removed.
* save FixedBitArrays as base64 in savegames.
* allow indirections in the string table - by prefixing the language string with '$$' the remaining text is interpreted as another string label to resolve.
* constexpr in palette code, also replacing #defines with enums.
Backported from Raze - without this there is no way to implement sounds that can unload themselves, because the existing ChannelEnded function is called when the sound is still active.
If the loader is allowed to go on, these objects will be linked into game structures and may do unpredictable things before the loader has a chance to abort at the end.
Some people apparently have to toy around with the engine's innards without fully understanding them. :(
When properly used the saveguards should never be triggered.
* Add FALLDAMAGE flag and add property to properly apply falling damage to the monsters
* Change name of propermonsterdamage property to propermonsterfallingdamage
It's possible for an actor to call Destroy() in a ZScript method (such
as Tick()) and then subsequently call A_StartSound() to play a sound.
Generally speaking this doesn't happen within a given class, but with a
class hierarchy, Destroy() may be called unbeknownst to a mod developer.
Even though checking bDestroyed is likely good practice, this ensures
that sounds won't be started on actors flagged for cleanup.
- If the hint text portion of a STRINGS lump entry begins with a '$', the value is treated as a string table lookup
Allows SECRETS strings to be translated via LANGUAGE lump. Reference: https://forum.zdoom.org/viewtopic.php?f=15&t=69827
Replaced explicit save of configuration file, which doesn't work after recent backend refactoring, with passing of CVARs we need to store to a new GZDoom process
https://forum.zdoom.org/viewtopic.php?t=69790
