Fix #849: Create parent directory in packageJSDependencies
Merge pull request #850 from gzm0/fix-packagejs-dirs

Fix #849: Create parent directory in packageJSDependencies
Fix #843: Fix ArrayOps.toList
Merge pull request #851 from gzm0/fix-array-ops-wrapper

Fix #843: Fix ArrayOps.toList
Generalize binding management.
Much more principled use of PreTransforms.
Merge pull request #852 from sjrd/refactor-optimizer

Refactor the optimizer