Fix examples/machine-code/garbage-collectors for tight equality

Reconcile store_thms with diverging names in db and val binding

Remove a stray occurrence of -- q -- as term-parser

Finish fixing machine-code for new by

build --selftest=3 now completes; I'm ready to merge into master.

Build more machine-code example thys with pat_assum

Removed trailing whitespace from all .sml and .sig files.

This affects over 900 files and was done using emacs's delete-trailing-whitespace
function in batch mode. Building the system with Poly/ML and Moscow ML seems to
work, so I'm hoping these changes don't break anything. Please complain if
they do!

A new version of files previously in examples/mc-logic.
Eventually examples/mc-logic will be deleted.