Update pdp-10 documentation
PDP-10 update

Implement keep-alive and os-requested reload functions of FE.
Preserve HW config flags during (re-) boot.
Allow IPL30 device to interrupt.
Add 18-bit DMA functions.
Implement DMA to/from I/O space.
Optimize DMA memory mapping - once per page, not once per byte.
Teach SHOW IO to report vectors and BR levels as well as CSR addresses.
Add DUP and KDP to Autoconfigure table.
PDP-10 update: LP20

Add Optical VFU support
Correct some inconsistencies with the hardware.
Add documentation and help.
Flush output file after 10 seconds of idleness to allow external watchers/processors to access entire job without forcing a simulator halt or detach/attach.
Make CR return to column 0, not column 1.
Make DAVFU contents accessible via SHOW.
Initialize RAM structures on power-up reset, but not reboot.
PDP-10 Update: TIM

Fix subtle errors in timer/timebase implementation.
Document mechanisms.
Reduce magic constants by using what the OS sets via wrint.
PDP-10 update

Halt code for Console FE errors
PDP-10 update: CD20

Make the card reader work on TOPS-10 and TOPS-20.
Augmented Image ECO was not implemented.
Simplify UI by defining commands for the various options/models emulated based on the simulator being built.
Document, and make the help conditional on model where that reduces clutter.
Deal with <CR><LF> reading ASCII files (file is opened 'rb' in scp's attach ; it shouldn't be.
Add translation support for DEC 026/029 full 7-bit ASCII, an ANSI standard & used by TOPS-10/20.
Deliver EOF at the correct time(s).
Preliminary support for update to card image spec being negotiated with the author.
PDP-11/VAX update: SHOW IOSPACE

Teach SHOW IOSPACE to output vector and BR addresses as well as CSR addresses.
SCP: Prevent use of uninitialized pointer.
PDP-11/VAX Update: NPR to/from IO Space

Matches PDP-10 change.  Necessary for KDP, harmless otherwise.
Fix CR builds

On platforms where the translation code default is dynamic, the default table pointer can't be const.

Remove const from the table pointer.
PDP10 update

EA calc of interrupt instructions is an extension by SimH, and performed incorrectly.  Indirect references are resolved in current context, not exec mode.

Since the Console Execute emulation takes advantage of this extension, correct it to calculate the EA in EXEC mode.
Merge remote-tracking branch 'origin/master'