[Simh] KL10E support in SimH

[Bob Supnik]

I've never been very interested in duplicating other people's work, so 
I've not looked into implementing the extended KL10 (KL10E) on SimH.  
Ken did an amazing job on KLH10.

If someone wants to try porting KLH10 over to the SimH environment, note 
that SimH is a single-threaded program that schedules its own 
pseudo-threads, while KLH10 uses operating system processes to simulate 
IO devices and their asynchronous behavior.  Also, the KL10 used a 
completely different set of IO interfaces than the KS10.  I was able to 
borrow code from the PDP-11 for the KS10 devices; the KL10 will need an 
entire unique set.

/Bob