Subset of commands ready for prototype 4
========================================

*0:    CHAIN (send to previous keyboard handler)

*1..79: XStrings

*89:   togle INS

*100:  Disable KEYB
*101:  Enable KEYB

*140:  int 5h  (Print Screen)
*141:  int 19h (Ctrl+Alt+Del)
*142:  int 1Bh (Break)

*150:  flush cache
*151:  warm reboot
*153:  power off
*154:  suspend

*160:  NOP (absorve)
*161:  set PAUSE bit
*163:  print Decimal char

*168:  alternative character intro: reset
*169:  alternative character intro: release
*170..179:    alternative character intro: numbers 0..9

*200..234: COMBIs