* Enable SECTORSPECIALAFTERTHINK since we probably really want to use that sloped lava wave in RVZ.
* Allow for infinite lives to be set via the setlives command/Pandora's Box.
* Refactor P_DoFiring(), with guidance from Sal.
* Correct the CRAWLA HONCHO\nCAN NOW BECOME\nSUPER CRAWLA HONCHO sliding movement in non-green resolutions.
Additionally, rename any remaining "srb2.srb" to "srb2.pk3" in the main source code files. Not sure whether to bother dealing with srb2.srb/srb2.wad mentions in project files for now.
Core and SDL2 are two separate targets now. Core is a static library
that is linked into SRB2SDL2. The sources for both are separated.
When using an IDE like Visual Studio or Xcode, the source code
organized into groups that explain what that group of sources does.
In the future, "Main" could be split into a few more groups based on
file prefixes, but I think the way it is set up works for now.
Makefile targets are not affected by source_groups and typing `make`
will automatically compile both the "Core" library and SRB2SDL2
itself.
