Asynchronous Multiplexer and Console Support

scp.c, scp.h, sim_defs.h
     - Added commands:
          SHOW MULTIPLEXER (MUX)
          SHOW TIMERS
     - Added facilities/APIs:
          sim_activate_after - time specific event scheduling (vs instruction scheduling) API visible, optional separate thread implementation in a later revision
     - Changed Commands:
          SET CONSOLE DEBUG no longer affects global debugging, but merely debugging for the console subsystem.  Use SET DEBUG and SET NODEBUG to affect global debugging.
     - Added Asynchronous polling support

sim_tmxr.h, sim_tmxr.c
     - Added Asynchronous capabilities to the multiplexer subsystem to avoid polling for input and to deliver input data instantly when it arrives instead of delaying for up to one or more full simulated clock ticks.
     - Added debug trace support
     - Added statistic tracking of total bytes transmitted on each line
     - Added more aggressive attempts to flush transmit buffers when they fill before dropping tranmitted characters
     - Fixed status return of tmxr_putc_ln to return SCPE_LOST if the transmitting line isn't connected or buffered.

sim_console.h, sim_console.c
     - Fixed issue where connections to console telnet sessions would succeed for the first connection, but hang indefinitely for additional connects without rejecting due to all lines being busy.  This is handled by using an internal device and unit to hang the required polling on.  Connection polls happen once per second.
     - Added console debugging/trace support.
     - Added Asynchronous capabilities to the console subsystem to avoid polling for input and to deliver input data instantly when it arrives instead of delaying for up to one or more full simulated clock ticks.
     - Added tmxr_set_console_input_unit() API to support asynchronous simulator console I/O

sim_timer.h, sim_timer.c
     - Added SHOW TIMERS support
     - Added mechanism to capture the timer the simulator uses for its clock tick and make this timer globally available for other uses

PDP11/pdp11_dz.c
     - Added debug trace support

PDP11/pdp11_vh.c
     - Added debug trace support
     - Changed timing mechanisms to not assume that the count unit service routine calls measures the passage of time, and created a separate unit to measure time.

VAX/vax_stddev.c
     - Added call to tmxr_set_console_input_unit to leverage Asynchronous console I/O
Asynchronous Timer Support

    scp.c, scp.h
	- Change the sim_clock_queue event list to be terminated by the value QUEUE_LIST_END instead of NULL.  This allows easy determination of whether a unit is on a list since when it is not on a list the next pointer is NULL.
	- standardized the usage of UPDATE_SIM_TIME
	- Added support for internal/pseudo devices to support the TIMER and CON-TEL pseudo devices (to enable and disable debugging)
	- Reverted to the prior "SET CONSOLE DEBUG" command semantics since the console debug can be manipulated via the generic "SET <dev> DEBUG" command (i.e. SET CON-TEL DEBUG=TRC;XMT;RCV)
	- Changed "SHOW TIMERS" to "SHOW CLOCKS" to display the current calibrated timer information
	- Added sim_is_active_bool API to return the boolean active status avoiding the potential work walking the list when most callers aren't interested in the event firing time
	- Fixed run_boot_prep to properly record the not queued status of any units which are removed from the sim_clock_queue during initialization
	- Added display of DEBUG, NODEBUG options to the SHOW SHOW command

    sim_timer.c, sim_timer.h
	- Added asynchronous timer capabilities with support for calibration and idling
	- Added internal/pseudo device to support debugging of Idle, Calibration and asynch timer activites.
	- Added suppression of timer calibration when idling has occurred

    sim_tmxr.c, sim_tmxr.h
	- Added tmxr_activate_after and macro definition for sim_activate_after to invoke it for proper behavior with multiplexer devices
	- Added all polling units to the standard timer queue when dropping back to the simulator command prompt to accommodate the potential to disable asynch mode
	- Fixed synchronization to operate with pthread synchronized asynch queue and proper stopping of poll when dropping back to the simulator command prompt
	- Fixed calls to select to have a timeout with properly ranged tv_usec values and dealt with possible EINTR return from select

    sim_console.c, sim_console.h
	- Changed internal/pseudo console telnet device name to CON=TEL
	- Reverted to the prior "SET CONSOLE DEBUG" command semantics since the console debug can be manipulated via the generic "SET <dev> DEBUG" command (i.e. SET CON-TEL DEBUG=TRC;XMT;RCV)
	- Fixed synchronization to operate with pthread synchronized asynch queue and proper stopping of poll when dropping back to the simulator command prompt
	- Fixed calls to select to have a timeout with properly ranged tv_usec values

    sim_defs.h
	- Added necessary unit fields to support asynchronous timing activities
	- Added asynchronous macros to support async timing activities
	- Fixed asynch pthread only macros (not using AIO_INTRINSICS).
	- Fixed the definition of the UDATA macro which was never adjusted to accommodate the insertion of 2 extra fields in the unit structure and thus made the initialization of the unit wait field meaningless.
	- Changed the NOQUEUE_WAIT value from 10000 to 1000000.  This is only used when the sim_clock_queue is empty, which normally never happens on any simulator since they all have clocks and/or other frequently polling devices.  With asynchronous multiplexer and timing support the queue is often empty and this value is then used when calculating idling delays.  If it is too small, idling will be inefficient.  Being large should not be a problem otherwise.

    Interdata/id16_cpu.c
	- removed test of sim_idle_enab before calling sim_idle

    Interdata/id32_cpu.c
	- removed test of sim_idle_enab before calling sim_idle

    vax/vax_cpu.c
	- removed test of sim_idle_enab before calling sim_idle

    vax/vax_stddev.c
	- converted CLK device to use the internal timer service API sim_activate_after to leverage asynchronous timing when available
Asynchronous Support

    scp.c, scp.h
	- added sim_uname (Unit Name) API to simplify places which might want to display it (mostly debug messages).
	- added support for clock co-scheduling
	- added debugging to trace event queue activities

    sim_defs.h
	- added support for clock co-scheduling
	- added support for sim_uname (Thread local storage macro)
	- added support for debugging to trace event queue activities
	- simplified debug code by using sim_uname
	- fixed support macro for sim_is_active when asynch timers are in use

   sim_rev.h
	- fixed nested comments

    sim_tmxr.c, sim_tmxr.h
	- added support for clock co-scheduling
	- simplified debug code by using sim_uname
	- added support for devices which poll for output on different units

    sim_timer.c, sim_timer.h
	- added support for clock co-scheduling
	- fixed asynchronous clock calibration to smooth out calibration adjustments
	- simplified debug code by using sim_uname
	- added ability (when running with asynchronous support) to explicitly disable or enable asynchronous timer support.
	- changed sim_timer_inst_per_sec to return a double value since the result is always used in a double expression and integer overflow could occur under strange timing conditions

    vax/vax_stddev.c
	- converted from simulator specific clock co-scheduling to generic clock co-scheduling.

    vax/vax_cpu.c
	- added EVENT and ACTIVATE debug flag (SET CPU DEBUG=EVENT;ACTIVATE) support

    pdp11/pdp11_dz.c
	- converted from simulator specific clock co-scheduling to generic clock co-scheduling.

    pdp11/pdp11_vh.c
	- converted from simulator specific clock co-scheduling to generic clock co-scheduling.

    pdp11/pdp11_xq.c
	- converted from simulator specific clock co-scheduling to generic clock co-scheduling.
Merge branch 'master' into AsyncTmxr

Conflicts merged and missing changes in new modules added as needed for clock co-scheduling.
Finish migration for simulators to use generic clock co-scheduling and sim_activate_after for scheduled delays
Changed examine register range to summarize redundant (duplicate) output.
Fix sim_tmxr flag settings to avoid an overwrite which was introduced when the dynflags was added
Add display of the registered clock device
Fixed typo referring to auto configuration information
Added calls to sim_register_clock_unit for simulators with clock devices
Added UBA register descriptions
Fixed register definition for the pak array which saved and restored the wrong content (not all of it) due to the internal longword alignment of the struct rqpkt.
Changed to use sim_clock_coschedule and sim_activate_after where appropriate
Fixed register definition to properly reflect the size of the stats structure.
Added register definitions and logic to allow reasonable SAVE/RESTORE behavior.
Merge branch 'master' into AsyncTmxr