Fix behavior of rlabel with VTA_BaseLine.

This fix is most noticeable with rotated labels.
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
Merge remote-tracking branch 'origin/master' into patch
Avoid warnings with lens-4.0

This change will cause warnings when compiled with lens<4; I did not feel it was worthwhile using CPP to avoid this
Build with lens<4.

This fixes up changeset 7f3ed3166913133cb0f97d89356b4ff7ee8531fb with a modicum of ugliness.
Merge pull request #26 from DougBurke/patch

- Fix behavior of rlabel with VTA_BaseLine.
- Many changes to make code compatible with -Wall