PDQ-3: Latest update from Holger Veit

- removed cycle counting in CPU, the sim_interval issue
- fixed the Console multiplexer logic; it now works with SET REMOTE TELNET= and SET CONSOLE TELNET=
- commented testhdt.sim
- changed run.cmd to try to execute either VStudio or mingw executable, in this order.
- changed printf messages to use sim_printf

Possible issues remaining:
- timer device polling, not yet debugged, the rate of 1.25MHz is likely still incorrect, so UCSD wall clock is surely wrong
- few instructions still to be trapped by opcode.debug - I haven't seen them in life code yet
- HD device still not yet finished; I'll pick this up again soon