Various controller fixes

Closes #936 and #937

See merge request STJr/SRB2!1914

This prevents axis events from trickling out of the menu and taking
effect in G_Responder when they aren't hitting the digital deadzone
needed to be mapped into internal menu key events.

Was erroneously mapping events inside the deadzone as key down and vice
versa.

MSVC project file works again! Supports Visual Studio 2022.

See merge request !1904

http-mserv: add SRB2-specific user agent string

See merge request STJr/SRB2!1893

Also fixed issues with the d_netcmd.c file/folder adding logic.

Remove PF_SPINNING upon use of any jump ability, so that directionchar works properly

See merge request !1429

Dynamically allocate space for a state's action field

See merge request !1478

Extend the length of the Connect via IP textbox.

See merge request !1410

Don't force bit depth to 8-bit when setting default video mode

See merge request !1733

Metal Sonic boss fight fixes

Closes #93 and #931

See merge request !1896

Fix a few rendering errors

See merge request !1901

Credits go to Lactozilla

This renders the "quadrant hack" and ZenNode largely useless

Fixes random invisible walls and possibly more errors

Increased maxsend

See merge request !1895

In environments without zlib installed, png would fail to build since
it can't find zlib.h. The zlib build's generated public include dir
needs zlib.h to work.

openmpt fails to build because it can't find Rpcrt4, which is not a
necessary link under mingw, but exists in some mingw-w64 toolchains.
It is only needed for MSVC.

Add haptic functions for Lua scripting

See merge request !1872

Add gamepad library and hooks for Lua scripting

See merge request !1871

Some hacks from the snake minigame patch have been removed as they are
no longer needed.

See !1870

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

Fix callcount typo

Closes #922

See merge request !1890

Matching Ring Racers. Previous move was actually a mistake on the Kart
port. Done so there is never a condition where the interpolator isn't
removed.

Fixes a crash that occurred frequently in special stages/NiGHTS.

[Snake Controller Fix] fix NONET builds

See merge request !1888

Fix PolyObject visibility/tangibility constants

See merge request !1886

Dynamic slope vertices: Allow untagged vertices which don't move

Closes #917

See merge request !1885