* New: Added autocomplete attributes for Gift Aid fields.
* Fix: Ensure Gift Aid only displays for Pound Sterling currency.
* Fix: Ensure the Gift Aid "long explanation" displays correctly when using form grid shortcode.
* Fix: Validation was not respecting the option to use the Billing Address field as the Gift Aid address.
* Fix: The {download_declaration_form} email tag will now not output any text/link if the donor has not opted into Gift Aid.
