Add flag to line slopes for even more slope copying

See merge request STJr/SRB2!1550

Fix gme support being effectively disabled

See merge request !1586

Fix #649

Closes #649

See merge request STJr/SRB2!1604

Polish the Lua input library

See merge request STJr/SRB2!1598

Implement folder loading

See merge request STJr/SRB2!1568

Refactor weather switching (fixes #541)

Closes #541

See merge request STJr/SRB2!1498

V_DrawCroppedPatch(...) Lua exposure and improvements

See merge request STJr/SRB2!1316

Add generalized slopes in UDMF

See merge request !1530

Make the colormap returned by v.getColormap() writable.

See merge request STJr/SRB2!959

Makefile: Improve gcc detection

See merge request !1608

Make next compile again

See merge request !1611

Add my full name in the credits

See merge request STJr/SRB2!1610

Wasn't working for me until I fixed it.
Turns out gcc really doesn't like giving its name out.
Most of the time it reads argv[0].

Multiplayer Bot Features (aka AddPlayer)

See merge request STJr/SRB2!1383

Give Coins drop shadows

See merge request !1591

Previously took only the filename, so the directory
component was stripped. This broke dependencies for
basically every file.

Fix #492

Closes #492

See merge request STJr/SRB2!1431

Fix console aliases bypassing CV_NOLUA

Closes #619

See merge request STJr/SRB2!1573

Revert netvars to user value after demo finishes playback

See merge request !1578

Fix for #551

See merge request STJr/SRB2!1590

P_ZMovement: add a P_MobjWasRemoved check after P_CheckPosition, so we can bail out if the mobj was removed (by Lua most likely)