use lowercase [smtp] as written in the docs
override HTML title parsing with a `data-title="...` attribute

If you don't use a <h1> to markup your post's title (but h2), it
is no longer possible to reliable detect the site's title.

E.g. you have a single page with only one <h1> and that's the
*real* title of that page. But on the other hand, it is also
possible, that the <h1> tag is just your website's name and the
actual post title is marked up in <h2>.
override API location with `data-prefix="..."`
Merge branch 'feature/data-attributes'