Don't cut momentum if landing in a roll

See merge request STJr/SRB2!972

Cppcheck fixes

See merge request STJr/SRB2!967

Allow transparent parts in translucent FOF and PolyObject planes

See merge request STJr/SRB2!978

Sync turnobjs for polyrotate_t thinkers in netgames

See merge request STJr/SRB2!979

sdl/i_main.c: while we're here, split all the logging initialisation code into a separate function, to make main function more clean

(though that said we don't officially care about the win32 folder files anymore)

V_Init: count to NUMSCREENS, not NUMSCREENS+1 (though I can't help thinking this one might have been deliberate somehow?)

Polyobj_rotate and related: change "origin" to vector2_t since all it needs is x/y and not any of the new stuff for vertex_t

This way, if for some reason the ghost has no skin, nothing should spawn at all

Effect 6 flag allows cutting of cyan pixels on FOF and PolyObject planes (even if they're translucent)

Deprecate FixedRem.

See merge request STJr/SRB2!952

Move drop shadows to the ceiling for objects in reverse gravity

See merge request STJr/SRB2!973

Clean up some movement code

See merge request STJr/SRB2!912

Traceback

See merge request STJr/SRB2!974

Fix waypoint sequence desyncs

See merge request STJr/SRB2!975

Fix the "Custom skincolors" branch not compiling with GCC 10.

See merge request STJr/SRB2!966

NOWIPE fixes for colormap and title card wipes

See merge request STJr/SRB2!962

Add back side wall scrollers & allow using offsets for tagged wall scrollers.

See merge request STJr/SRB2!955

Possible fix for dedicated server crashes (aka the msvcrt.dll!_mbscat crash)

See merge request STJr/SRB2!963

Allow input buffer to hold more than 64 tics

See merge request STJr/SRB2!950