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.

In exchange for preventing access to any mobj_t userdata outside levels, including player's own mobj_t.

* Store gravflip (resolves #206) and destscale in starposts. (Using the same field, taking advantage of the fact that object scale will always be positive!)
* Update the function signature of P_MixUp to accomodate both it and drawangle instead of doing it outside of the function.
* If the player is spawning from the start of the stage and it's from the ceiling, be in fall frames as requested (resolves #191).

Since the enum type is implementation-defined, and could be either signed or unsigned.

* Strip the word "function" from INLEVEL error messages, since they're now shared between access and function cases.
* Move it into lua_script.h, so it's available to everything that needs it.

Fix lua scripts erroring on the title screen because they're run there but it's not counted as GS_LEVEL (aka #168).

I know this isn't my branch, but found several reference haemmoragers and figured it'd be appropriate to commit here.

# Conflicts:
#	src/p_setup.c

There is no lapfinishedtime because [mare]finishedtime refers to when Egg Capsule is destroyed. That concept does not apply to laps.

* player->drone mobj variable
* P_MoveNiGHTSToDrone, will change later

There is no lapfinishedtime because [mare]finishedtime refers to when Egg Capsule is destroyed. That concept does not apply to laps.

There may not be a point to this, other than to be consistent with how spheres are tracked. If non-special stage NiGHTS should tally a ring bonus, this may be useful.

OLD SPECIAL STAGES:
* Spheres in old special stages instead of rings!
* Individual timers in old special stages instead of a global one!
* Old special stages use a variant of the NiGHTS HUD now!
* Special stage damage in old special stages loses 5 seconds of time instead of 10 rings/spheres!
* All damage gained through old special stages is converted to special stage damage! As a consequence, the special spikeball has no need to be special anymore.
* Made emerald gaining function be based on special stage number rather than gained emeralds!
* Consistency with...

NiGHTS SPECIAL STAGES:
* Spheres now flash in bonus time. https://cdn.discordapp.com/attachments/400761370800422922/452590553100713984/srb20032.gif
* Sphere and ring mapthingnums are now less fucked up in 'em. (Rings are 300, same as usual, while Spheres are now 1706 replacing NiGHTS Wings.)

SPECIAL STAGES IN GENERAL:
* useNightsSS is now dead. Each individual special stage is now assessed for NiGHTS-mode behaviour based on maptol & TOL_NIGHTS.
* CRAWLA HONCHO\n CAN NOW BE\n SUPER CRAWLA HONCHO end tally modification now also includes a mini-tutorial on turning super. https://cdn.discordapp.com/attachments/400761370800422922/452844894113759233/srb20036.gif
* SONIC GOT A CHAOS EMERALD? https://cdn.discordapp.com/attachments/400761370800422922/452623869497573386/srb20034.gif

NiGHTS NON-SPECIAL STAGES:
* Colour Chips and Star Chips! Replaces Spheres and Rings of NiGHTS Special Stages.
* Colour Chips turn yellow in bonus time.
* Ideya!
* Its own "drowning" music!
* All of the object types for Dream Hill.
* GIF: https://cdn.discordapp.com/attachments/400761370800422922/452844894113759233/srb20036.gif

RANDOM BS:
* Turn super with the spin button instead of the jump button!
* Followmobj now correctly set with P_SetTarget instead of pointer assignment.
* Emerald hunt uses new sprites!
* Made unlock noise different from emblem gain noise! (It's the CRAWLA HONCHO CAN NOW TURN yadda yadda sound from S3K now.)

Smiles follow-mobj initial support! Still using a Lua hook to follow closely behind, but now it doesn't need to be a generic thinkframe. Woo!

* Expose player->outofcoop to Lua.

Big commit, sorry. I broke several things trying to get other things to work and it's only now that all the code that worked yesterday works today!

*P_LookForEnemies is now side-effect-less and only provides a pointer to the found mobj
*player-jumping is dead, long live PF_STARTJUMP
*per Mystic's request, CA2_GUNSLINGER has a targeting icon. It also has a more restricted vertical aiming range.
*mobj for this is in the game as requested
*fast teetering animation flag
*general code cleanup

Mystic wanted it, just play it - too busy to give proper commit description. Will outline everything it is in the merge request when that happens.