Release 6.4.1

Shopclass 6.4.1

This release fixes two security issues: custom-field values that could run script on a listing
page, and an e-mail change link that also worked as a password-reset link. It also fixes a false
mod_ssl warning on the mail settings page.

Full changelog: https://github.com/mindstellar/shopclass/blob/6.4.1/CHANGELOG.md