Metal Sonic boss fight fixes

Closes #93 and #931

See merge request STJr/SRB2!1896

Fix a few rendering errors

See merge request STJr/SRB2!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 STJr/SRB2!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 STJr/SRB2!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 STJr/SRB2!1870

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

Fix callcount typo

Closes #922

See merge request STJr/SRB2!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

Better viewpoint switching

See merge request !1875

Fix Download Consent/Snake minigame not having controller support

Closes #836 and #835

See merge request !1883

This would conflict if your shift key is bound to a control =((

Fix suspicious statue still being tangible for ~40 tics after spawning lance-a-bot

Closes #856

See merge request !1882