Floorsprite fixes

See merge request !1443

This fixes the texture of the floorsprite sometimes facing the wrong way, since plane rendering can change the view angle.

Fix addons with custom gamedata not loading

Closes #473

See merge request !1427

Fix unused variable warning when USE_APNG is not defined

See merge request !1343

Fix sigsegv caused by bad target check in A_Custom3DRotate

See merge request !1430

Fix OpenGL V_DrawCroppedPatch (Fixes #452)

Closes #452

See merge request STJr/SRB2!1412

(Apparently Kart made this exact fix 2 years ago and it was never backported?)

Fix compile warning on Windows

See merge request !1426

More final tweaks for 2.2.9 I guess

See merge request !1417

Papersprite dropshadows no longer askance

Closes #409

See merge request !1408

Fix a few renderflags oversights in OpenGL

See merge request !1422

Fix for #422

Closes #422

See merge request !1425

Remove misplaced SetShader call in CompileShaders (Fixes #402)

Closes #402

See merge request !1423

Use double precision in R_StoreWallRange sloped seg culling calculations (Fixes #434)

Closes #434

See merge request !1424

Print a backtrace when SRB2 crashes in a Unix-like environment.

See merge request !1288

Fixes culling issues in CEZ2 skybox

Check if GME_VERSION is defined.

See merge request !1372

Fix CA_BOUNCE height when flipped (Fixes #428)

Closes #428

See merge request !1373

Disable pausing during score screens in marathon mode

See merge request !1416

Fix translation colormap cache rebuilding using the old translation enumerations (fixes #443, #449, #459)

Closes #443, #449, and #459

See merge request !1421

Fix thing scale mismatch in R_DrawVisSprite. (Fixes #458)

Closes #458

See merge request !1420

Revert "Merge branch 'player-speed' into 'next'"

Closes #466 and #471

See merge request !1418

This was causing a buffer underwrite too. Lovely.

Fix "implicit declaration of function 'DEH_TableCheck'" warning

See merge request !1419

Nice UDB config there, SRB2.

See merge request STJr/SRB2!1354