remove "mainline compatible mapping"
remove VGA size override option
remove "allow reset by port 92, keyboard" etc. options
remove non-recursive page fault
remove EMS emulation
remove KEYB.COM and keyboard layout code
remove SetVal(), menu.cpp, and some d3d code
remove some WIN32 and OS2 #ifdef blocks
remove WIN32 and Direct3D code.
remove C_IPX and C_NE2000 from dosbox.cpp
remove frameskip
remove frameskip option
remove aspect option
remove aspect option and support