Distinguish between taggable/untaggable constructors in the grammar.
Named 'constructors' and 'values' in the grammar respectively.
(e.g., don't tag Num b.c. it's a value, don't tag Binding b.c. it's a
macro arg, do tag If)
Or, Cond, Let, macros all now working as they should.
Also, store and print transparency marks.