* Optimise them even further... AGAIN! Using an offset-based system rather than a multiplication-based one...
* Again, tweak the spawning code to take maximum advantage of these gains.
* Fix potential crashes with MT_NULL mace/chain types supplied.
* #ifdef out the height-clipping code. It needs more TLC than I can give it right now, and the existing behaviour is less obviously broken (sadly enough).
* Fix chainmace points, which were apparently broken without anyone realising.

* Revamp mace creation again to potentially serve as the foundation for further optimisation (and also not rely on a while (1) loop, which easily went wrong several times whilst I was making changes to it).
* Fix minor typoes and other small tweaks in the P_MaceRotate function, which I'm probably about to rewrite again anyways...

* Completely rework how mace/chainbars are spawned to reduce the number of matrix multiplications required EVEN FURTHER!
* Reimplement the maceretry solidity stuff (effect 4).
* Flip the mminlength stuff so that existing dev maps don't break badly.
* Fix hacky chainbar grabbing.
* Tweak height of tinychain a smidge.

* Fix ability to turn chains (still disabled by default, just at least want the option...)
* Replace max speed setting with a "minimum chainlink distance" setting - if greater than zero, that many chains will not be spawned from the center outwards. Doesn't affect the head of the chain at all, since otherwise what's the point? :V

* Handle all chain objects as a hnext/hprev chain.
* When removing mobjs with hnext/hprev, "repair the chain" (make the h links meet).
* Fix hidden slings, which I accidentially broke when I revamped maces the first time.
* Kill MF2_MACEROTATE. Not needed for anything anymore.
* P_MaceRotate now available to Lua to make up for it.
* Related: Made modifying hnext/hprev using Lua safer, so it keeps the reference counts in play.

Zoning out

See merge request STJr/SRB2Internal!133

# Conflicts:
#	src/sdl/i_system.c

Linux limbo

See merge request !228

SOC sanitizing

See merge request !227

Console key breakfast

See merge request !226

Turns out compiling for Linux 32-bit using the Makefiles never actually defines LINUX! Apart from that, most of the existing Linux-specific code in SRB2's source code (except for tmap.s) actually uses __linux__ instead anyway

Eat unprintable keys too, since there's no reason to feed them to G_Responder anyway when the console is open

Make CON_Responder eat Ctrl+key combos that have no effect, instead of passing the key on to G_Responder

Total reorganisation of z_zone.c/h, added doxygen-compatible comments to all functions and additional regular comments where appropriate, changed purge tag macros to an enum list

Clean up z_zone.h's function protos to look more readable like m_random.h, don't name functions with "2" if not using PARANOIA or ZDEBUG

also, Z_Malloc/Calloc/Realloc are now macros of the "Align" versions, regardless of ZDEBUG or not

Fix net commands not always being freed

File loading cleanup

See merge request STJr/SRB2Internal!129

Fix SOC/Lua loading messages to display full names or even display at all (for PK3s at least), and otherwise some cleanup of existing code for the messages.

Also, I moved lua_lumploading on/offing to LUA_LoadFile.

Stop leaking names via metadata.

See merge request !223

Fix for "playdemo" not working with custom home paths

See merge request !221

Hotfix for "LUA PANIC" crash when joining a netgame

See merge request !222

General sky fixes

See merge request STJr/SRB2Internal!132

Fixed sky-sky thok barriers showing HOM (turns out the floor and ceiling share the same plane, so I've modified the code to account for this)

Additionally, place some optimisations in both software and OpenGL; in particular one has been added for when all of back and front sector (floor and ceiling) is sky: since everything is "open" anyway, we can simply the usual checks involved.