Remove P_FindSectorFromLineTag and P_FindLineFromLineTag

See merge request !901

More thinker refactoring

See merge request STJr/SRB2!900

elevator_t cleanup

See merge request !896

# Conflicts:
#	src/p_saveg.c

Add a minimum delay between connections

See merge request STJr/SRB2!889

Fix a few strncpy bullshit

See merge request STJr/SRB2!895

Netgame $$$.sav code cleanup

See merge request !894

This reverts commit 2e27f32d.

Fix mouse being grabbed in intermission and cutscenes

See merge request !891

Make P_AddRaiseThinker more configurable via function parameters (needed for UDMF)

See merge request !899

Clean up the plane thinker cleanup

See merge request !897

Do the same with writing ARCH_FFLOOR values in Lua archiving code (reading was already dealt with years ago)

created P_GetFFloorID to get an "ID" of an FOF in its target sector (an opposite to P_GetFFloorByID you could say!), rewrote floor/ceiling rover archiving code to use both P_GetFFloorID and P_GetFFloorByID

we don't actually need put/get pointers at all (plus with everything put into functions they wouldn't work properly anyway)

Plane movement thinker cleanup

See merge request !880