Ability to remove license key

Hi all,

The plugin's new ability to store the license key, without the need of a separate plugin, is great, but we have one issue.

In the rare instances that clients move away from us we need to be able to remove the license key but the field is a required field. Can I ask that you remove this attribute to allow previously licensed sites to be returned to an unlicensed one?

Cheers,

Will