• PC-98 FM synthesis fixed not to initialize itself
  again when rebooting, which fixes a problem with
  garbled FM synthesis after rebooting.
• Removed some now-unnecessary SDL Video quit/init
  calls from Windows builds.
• machine=pc98 now starts entire emulation in PC-98
  mode instead of booting up in IBM PC mode and
  switching to PC-98 mode.
• Initial "BIOS" startup screen now operates in
  PC-98 mode when machine=pc98.