Convenience helpers for more simply accessing data passed to applications through the environment that may have types and/or defaults

We're all used to tools that enforce _total_ coverage numbers, but this gem tries for something different. Instead of keeping your whole project above some threshold, we treat the coverage of _each class_ as a testable quality and then enforce that coverage as part of the test suite!

We've written code that merges/cascades default configuration, config-files, environment variables, and cli-passed arguments _too many times_. This gem intends to distill that into a configuration hash describing those controls and relationships, so that users can supply values in multiple ways.