v0.0.2

Changelog:

• opts() slightly refactored to produce more constructive output when no
  option names are provided. You can now use opts(env = package_name) to
  fetch a full named list of option values. (@dgkf #2)

• Generated roxygen2 documentation using as_roxygen_docs() is now more
  consciencious about R CMD check requirements, moving \usage{} to a new
  section titled "Checking Option Values". (@dgkf #2)