extruder-match: allow referring to array elements.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Allow reading config from IO objects.

This aids in testing, and it allows users of the framework to specify
configuration without creating a temporary file.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Add tests for queue runner.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Rakefile: clean up RuboCop warnings.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>