PDP-10 Update

Update documentation to reflect recent development.
Optimize FE reload to pull one test out of the critical path and to produce a unique stop code.
Merge branch 'master' into KDP
KDP: Handle KMC_UNITS better

No need for devices=n if only one is supported.

Force INITIAL_KMCS to be <= KMC_UNITS

Cleanup absolute reference to kmc_dev.