Cleanup for compile without ITS or BBN options.
Cleanup of interrupt handling.
Floating point code now passes random instruction tests with
minor off by +/-1 in lower half of long add/subtract instructions.
RP10 proper handling of not ready flag.
RP10 no seek interrupts while read/write to other drive.
TM10 Clean up off by one bits in upper status.
TM10 Added MT_LASTWD flag to indicate read of last word.
TM10 Proper handling of Record length error.
TM10 Added EOR flag.
TM10 Rewind at BOT now Illegal operation.
TM10A return channel flags as 1 rather then 0.
RH10/disk Handle reset CONO flag.
RH10/disk Generate parity on register read.
RH10/disk No registers can be modified other then attention when
one drive is doing read/write operation.
RH10/disk write register 0 without GO update command.
RH10/disk command to unready drive return RMR error.
RH10/disk Search/seek to invalid CHS returns immediate error.
RH10/RP06 write to error 2 and 3 registers work.
RH10/disk no seek interrupts set when other drive read/write.
