Simplify isCyclic.
No need for the isComputingCyclic property.
Define a macro for recursive memoization.
Test nullability.
Simplify nullability.

No need to invoke HMRDelay for a simple boolean recursively memoized
fixpoint.
Test cyclic nullability.
Define a macro for recursive memoized fixpoints.
Test cyclic concatenation parseForest.
Simplify parseForest with HMRFix.
Smarter descriptions.

Conflicts:
	Hammer/HMRParserCombinator.m
Name the reduction in parsing tests.
Simplify -description with HMRMemoize.
Don’t prefix cyclic instances of -description.

Fixes S -> S nonsense.
isCyclic is a fixpoint.
Simplify compaction.
Test compaction of cyclic alternation.
Compact cyclic alternations w.r.t self.
Compact shallow cyclic concatenation w.r.t. self.
Spacing.
Don’t set the name when it’s already set.