Dash state for Tails overlay (Closes #325)

Closes #325

See merge request !1210

Draw save files from outwards in

See merge request !1228

Credits Changes

See merge request !1200

Turn the lua sector lines hack into a macro

See merge request !1187

Set cvars directly from Lua

See merge request !1205

Add multithreading option for CMake

See merge request !1204

Only invoke the Lua API for mobj hooks that need it

See merge request !1209

Do not let previous wait commands affect COM_BufInsertText

See merge request !1207

Fix G_GhostTicker crashing trying to read netvars as ghost data

See merge request !1203

NPO2 span function optimization

See merge request !1201

Kick clients that fail to catch up with server gamelogic

See merge request !1208

CV_SetValue merged with CV_Set (same with CV_StealthSetValue and CV_StealthSet).

Also fixed possible issue with incorrectly reading the demo pointer due to the wrong type being passed to sizeof in G_ConsGhostTic

Model fallback

See merge request !1167

Bustable Wall and Floor flags.

See merge request !1163

Performance stats

See merge request !1186

R_FindPlane optimization

See merge request !1199

Apply step up/down to opposite plane too

See merge request !1192

Lua polyobjects

Closes #19

See merge request !1140

Make record attack's quick retry more consistent.

Closes #80

See merge request !1193

Fix OpenGL GIF recording crashing with gif_localcolortable disabled

See merge request !1196