update SeoField to use FieldTypeBase
update SeoField to use FieldTypeBase

In bolt 3.3-beta3 a new interface FieldTypeInterface was introduced, and as of bolt 3.3 as a whole the FieldInterface no longer work. This update changes SeoField to use FieldTypeBase instead.
mborn319/seo,bobdenotter/seo,bobdenotter/seo,mborn319/seo