Credit Tatsuru

See merge request !728

Fix fire shield being removed under lava

See merge request !729

Let clients rejoin the server without losing their status

See merge request !722

Rename R_IsPointInSubsector to R_PointInSubsectorOrNull/Nil

See merge request !719

MUSICDEF cleanup, fixes, and VERSION directive to opt into new format

See merge request !708

Fix "cam2_turnmultiplier" being unused in "next"

See merge request !713

This lets the host manually remove a body if they want,
without polluting the chat with redundant messages.

Disconnected players do not become IT at round start.

If all non-ITs are disconnected, the round ends.

If all ITs are disconnected, one of the non-ITs
becomes IT, or the round ends if in Hide & Seek.

The old name made it really easy to accidentally read
R_IsPointInSubsector as R_PointInSubsector, and anyway it
didn't even make sense...

# Conflicts:
#	src/g_game.c
#	src/p_setup.c

This is accomplished by simply preserving
the player's body after disconnecting.

Bodies will despawn after the number of minutes
specified by the "rejointimeout" console variable (float).
A value of 0 disables the feature completely.

Clients rejoining are identified by their IP address,
and may rejoin even if the server is full or joins are disabled,
for as long as their body remains.

From a technical standpoint, when the user disconnects,
the player they were controlling does not leave,
the underlying player_t just keeps working normally,
except it does not receive any input anymore.
When the user reconnects, they are simply "relinked"
to their player_t.

Those "soulless" players can be identified through
their "quittime" field, which is the number of tics
elapsed since the user disconnected, or zero
if still connected. "quittime" is exposed to Lua.

Fix title screen broken when leaving during resynch

This fixes player 2 using player 1's "cam_turnmultiplier"
instead of player 2's "cam2_turnmultiplier"

OpenGL drop shadows

See merge request !703

Put cv_exitmove in the server options menu

See merge request !704

The "VERSION" directive enables features available in a certain version of
SRB2. It may be used as "VERSION 2.2.0".

If you use strtok for (CR)LF, it'll skip the empty lines bruh.

Mapthing flag EXTRA DeHackEd constant

See merge request !705

Add FF_INTANGABLEFLATS as an alternative spelling for FF_INTANGIBLEFLATS

See merge request !702

Software dropshadows

See merge request !660