cleanup whitespace
remove whitespace in tests
[CHEF-3497] Document primary interface to mixlib-cli
[CHEF-3497] optionally store default values separately

This will make it easier for knife to apply config settings in the
proper order (default < config file < command line). It's not possible
to do without this patch because knife must parse command line options
to determine which config file to use.
Merge branch 'CHEF-3497'
Bump to 1.3.0 RC 0
Update to gem/package_task
bump version to 1.3.0 (release)