Version 0.3.0

We've removed support for the custom elements (<doh-script>, <doh-style>, and <doh-img>). Loading external resources by first using a DoH lookup does not work because once we have the IP address, there's no way to set the SNI field from JavaScript, so certificate verification fails. I suppose you could potentially do it over HTTP, but that would sort of defeat the purpose of DoH in the first place.