Update to Memberships

Due to malicious activity related to my "Liker" membership tier, I've decided to grandfather in the current users of the tier and open up a new tier that limits the amount of models a user can download each month.

The amount of downloads will roll over from month to month, and if there's a month that no downloads occur, no charge will be made for that month.

Thank you for understanding and feel free to reach out if you have any questions.