Prefer single-quoted strings.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Add test for out of order flag characters.

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

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Refactor string handling in spec/main.rb.

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