Add missing exports.

This update adds some missing exports from modules, removes un-used module imports, fixes one partial function, and minor documentation tweaks.
Add missing imports.

Adding to changeset 65b5308591dc0a837103b57651af4860c0d235db
Code cleanup: -Wall/hlint

Changes include: use -Wall for building; cleanup to avoid -Wall warnings; apply hlint suggestions; more use of Control.Lens