Tweaks to the planner

Tweaks to the planner

Mostly cosmetic changes, but of note:
  The planner now uses the alias-tracking contexts for mode analysis (though
    it does not actually yet do anything with this power; this change is in
    preparation for backward-chaining)
  DOpAMine unifications are now tagged with determinisim information, again
    in preparation for future work; these are all currently set to DetNon.
  DOpAMine and Python OPEmit printout is much more vertically compact.