Dump remaining codes

[lacostej]

I would like to be able how many codes are remaining for one app or for all. Something like

codes display -a xxxxxx
codes display --all

Again a parametrized output might be interesting (see #8)

[lacostej]

This set of commits adds support for the feature (except for --all). Feedback appreciated:

https://github.com/lacostej/codes/commits/display_and_output_formatting

[lacostej]

missing the --all parameter