New render features:
- Doom64-style color properties for sectors (i.e. different color settings for floor, ceiling, walls and sprites.)
- script versioning to account for syntax differences between versions.
- fully scripted inventory system.
- fully scripted menu system.
- scripted event system.
- printf-style string formatting function for ZScript.
- dynamic arrays for ZScript.
- more access to map data from ZScript.
- user definable actor properties.
- separation of scripts into UI and Play parts to have better access control
- exported obituary code to ZScript to allow more flexibility when handling special cases.
- SectorTagIterator and LineIDIterator classes to search for tags.
- added GetActorFloorTexture and GetActorFloorTerrain ACS functions.
- added new PRINTNAME_ constants for retrieving next and secret next level in ACS.
- per-sector settable fog density.
- fixed handling of sector action things with special trigger semantics.
- true color fonts can be defined in FONTDEFS.
- added a BOUNCE_NotOnShootables flag to address an old design bug in the bouncing system.
- added StealthAlpha actor property for defining a minimum visibility value of a stealth monster.
- and many more smaller additions and fixes.