Handle catalog flag as well as properties flag

[robmoore]

Addresses #54

[cmerrick]

Hi @robmoore, thanks for your contribution!

In order for us to evaluate and accept your PR, we ask that you sign a contribution license agreement. It's all electronic and will take just minutes.

[robmoore]

I can also add to the error message on line 698 so that it reads "No properties or catalog were selected", if desired.

[luandy64]

@robmoore If you can sign the contribution license agreement, I'll work on reviewing this

[cmerrick]

You did it @robmoore!

Thank you for signing the Singer Contribution License Agreement.

[luandy64]

Thanks @robmoore! 👍

[robmoore]

Not sure what your release schedule is but I was hoping to be able to use this change via Pypi. Any ideas on when that might happen?

[luandy64]

It should be out now, sorry about that.

[robmoore]

No worries! Just wanted to know what to expect. Thanks for the quick turnaround.