Add -q option, Travis CI, coverage

 * Add `-q` option for `--quiet`.
 * Add Travis CI build.
  * Just run some example commands with differing options to make sure they at least run on different platforms.
  * Run with coverage.
  * Flake8.
 * Update setup.py's classifiers to match Travis CI Python versions.

Please enable Travis CI and Coveralls for the main repo.
https://travis-ci.org/profile https://coveralls.io/repos/new