Added support for KI style interrupts. Added comments to CPU code.
Fixed bug in MUUO under KI. Fixed RH10 to work under KI. Fixed bugs
in handling of record space under TM10 controller. Added type casting
into DF10 code and verified it works correctly under 22 bit operation.
Started adding support for PDP6.
Major cleanup to code, set_interrupt() now only looks at 3 lower bits
to determine interrupt level. Some Copyright notices have been updated.
DC10 now handles modem control correctly. And will support up to 32 lines.
Modem lines start at a fixed value and follow the data lines.