graphs: moving to basis.
sets: adding adjoin-all.
compiler.units: changing definitions-changed to use a set.
compiler.units: simpler update-existing? check.
compiler.units: simplify checks.
compiler.tree.tuple-unboxing: simpler checks.
tools.scaffold: more use of hash-sets.
compiler.cfg.ssa.construction: more use of hash-sets.
compiler.cfg.loop-detection: more use of hash-sets.
classes.builtin: Add the BUILTIN: keyword which lets builtin classes show up in source files. Probably could use save-location to allow editing, but it seemed to break things.
math.statistics: Fix histogram and collect. Histogram used each-index even when it didn't need to.
help: Mismatched <PRIVATE PRIVATE> pair.
ui: change selected gadgets to a hash-set.
compiler.tree.dead-code.simple: curry live-values.
compiler: more use of hash-sets.
hash-sets: use push-unsafe from hashtables.private.
compiler: cleaner use of sets.
compiler.units: more use of hash-sets.
Fix some tests broken by recent definitions change.
parser: fix docs for filter-moved.