Update player->quittime while a Server is Idling, Attempt 2

Closes #1143 and #1119

See merge request STJr/SRB2!2254

Only Consider ExitLevel a Cheat When Used to Cheat

See merge request STJr/SRB2!2159

Add "allowflip" Parameter to P_DoJump

See merge request STJr/SRB2!2158

fix miniupnpc typo in features.mk

Raise the skin limit

See merge request STJr/SRB2!1466

OpenGL: Fix linedef type 10 not culling FOFs (Closes #438)

Closes #438

See merge request STJr/SRB2!1399

Make Dead / NoClipHeight Objects Immune to Death Pits (Resolves #553)

Closes #553

See merge request STJr/SRB2!2001

Copy Interpolation to Shields and Overlays, Splitscreen Overlays

Closes #997

See merge request STJr/SRB2!1992

Expose P_IsLocalPlayer to Lua

See merge request STJr/SRB2!1997

Rewrite M_DrawStaticBox

Closes #1014

See merge request STJr/SRB2!1990

Always Allow con_hudlines when Using devmode

See merge request STJr/SRB2!1987

Made filesearch aware of symbolic links

See merge request STJr/SRB2!1976

Update mobj floorz/ceilingz after a bustable FOF is destroyed

See merge request STJr/SRB2!1945

Implement perfstats options for LUAh_PreThinkFrame and LUAh_PostThinkFrame

See merge request STJr/SRB2!1932

Add transparency flag support to drawFill

See merge request STJr/SRB2!1881

Move player friction reset after movement code for lua qol

See merge request STJr/SRB2!1824

Fix line.sidenum[i] in Lua

See merge request STJr/SRB2!2252

made UPnP port mapping enabled by default

See merge request STJr/SRB2!2251

Fix rare but possible menu/console unresponsiveness bug (Resolves #700)

Closes #700

See merge request STJr/SRB2!1677

Expose a `constants` dictionary to Lua.

See merge request STJr/SRB2!1646