Heurist READ connector

I was worried about Heurist's future. Then I continuously and at length heard its creator stance and seen him act for years, and now I'm even more worried. Or rather, I'm worried about the continuous availability of people's data.

Heurist's XML file is a mess: lack of documentation (XSD url points to nowhere, XSD in the repo is not maintained up to date, no "vision" about it in an unwieldy documentation full of holes), unanticipated and unexplained bugs or evolutions, various interoperability problems due to interface breakages ... Talk about developper quality of life.

Anyway, I'll do it, as I already did in xHeimdall.
Cause somebody's got to do it, heh?