CMake support. Srb2win.rc still needs touchy, whatever.

2.2.6 preparation

See merge request STJr/SRB2!1050

Revert "Fix computation of very high pings"

See merge request STJr/SRB2!1053

This reverts commit 82dbe95e.

Fix GL y-shearing ignoring a Y-flipped transform

See merge request STJr/SRB2!1051

Marathon Run adjustments

See merge request STJr/SRB2!1048

Fix models that use sprite textures

See merge request STJr/SRB2!1049

Bruh Core Zone 2

See merge request STJr/SRB2!1047

Introduce a live event backup penalty for non MA_INGAME runs, since the change to saving time causes problems for this.

Hopefully fix the issue, which I can't recreate, of live event backups being created even if they shouldn't.

Add a small amount of extra info to the Evaluation screen for Marathon Mode, on request from multiple runners.

Fix the issue where custom exits with skipped intermission screens (notably, Black Core Zone 2 and 3) would cause the game to softlock when playing on a save file, or with a live event backup.

Restore SKINCOLOR_SUPERGOLD1-5 changes from 2.2.3

See merge request STJr/SRB2!1042

Fix custom skincolors being fullbright & signpost backgrounds using incorrect color shades

Closes #179 and #182

See merge request STJr/SRB2!1043

Whose idea was it to make the aPNG speed 1/2x by default?!

See merge request STJr/SRB2!1044

2.2.5 preparation

See merge request STJr/SRB2!1039

Remove Software tricks

See merge request STJr/SRB2!1036

Fix autoexec file trying to set netvars when joining from command-line

See merge request STJr/SRB2!1040

M_RATHON header text

See merge request STJr/SRB2!1041