Lua multitagging

See merge request STJr/SRB2!1292

# Conflicts:
#	src/doomtype.h

Fix vibing slope planes

See merge request STJr/SRB2!1335

Restore the viewpoint's angle in R_DrawPlanes instead (related to #404)

See merge request STJr/SRB2!1326

Replace the first entry in slope vertex thing taglists, instead of adding into them (related to #404)

See merge request STJr/SRB2!1333

Fix archived mobjs having no default blend mode and sprite scales

See merge request !1300

Improved text colormaps (Closes #222 and #359)

Closes #222 and #359

See merge request STJr/SRB2!1202

I messed up the multiplication order for texture scaling: it multiplied a floating point number with a fixed point number, instead of multiplying two floats and then converting the result into a fixed point number.

Add new skin flag SF_NOSHIELDABILITY

See merge request !1331

fix amy meeting herself in mario mode

See merge request STJr/SRB2!1330

Fix a crash in Picture_GetPatchPixel with PICFMT_DOOMPATCH formats

See merge request STJr/SRB2!1324

Make fiery spindust fullbright

See merge request !1317

Make Ring Drain sectors play the depletion sound instead of the ring sound

See merge request STJr/SRB2!1315

Fix animated skincolors in OpenGL (resolves #187, #247, #301, #370)

Closes #187, #247, #301, and #370

See merge request STJr/SRB2!1301

Player-Colored Elemental Fire for competitive gametypes

See merge request STJr/SRB2!1312

Fix double free occuring when unloading the intermission patches

See merge request STJr/SRB2!1304

Final lap text for circuit

See merge request STJr/SRB2!1303

Fix SPC looping on libgme versions >= 0.6.3

See merge request STJr/SRB2!1302

Fix intro crash

See merge request STJr/SRB2!1310

Add aPNG downscaling

See merge request STJr/SRB2!1197