remove last twitter remnants

add option to ignore rel-alternate as2

bugfix

* remove twitter support

fix multiline posts with smashed together paragraph tags

closes #117

remove instagram

escape html tags when creating html version

Return h-event location as an embedded h-card

fix authorship in some cases

accept webmention verification for pages with only mf1

if the document contains a link to the target, but that link is not in the parsed result, don't return an error, but also don't return the parsed document