Regress test of deferrables. Fix dart, factor.

Regress test of deferrables. Fix dart, factor.

Add a regression run to Travis that enables hard deferrables but
omits optionals so that we can test to make sure that all the
requirements are met for self-hosting in stepA.

Cleanup up some of the soft/deferrable/optional markings.
Deferrables are what will be needed eventually to self host but aren't
needed for the immediate next steps. Optional aren't even needed for
self-hosting but are nice things to have.

Also:
- Sync dart step9 and stepA with step8. Do not eval macroexpanded
  forms in macroexpand form.
- Fix stepA of factor which was missing some fixes from step9.
- Increase test timeouts in top-level Makefile for guile and io.