internal: Refactor config loading some more. * Remove fixup code in the app to make the app config class more standalone. * Remove support for old-style variants... maybe bring it back later. * Try and fix various bugs introduced by subtle config value overriding order changes.

*.pyc
*.egg-info
.cache
__pycache__
venv
tags
bower_components
node_modules
build/lib
util/messages/_cache
util/messages/_counter
dist
docs/_cache
docs/_counter
foodtruck/static
piecrust.egg-info
piecrust/__version__.py
.ropeproject