closes #24

* closes #23
* major refactor of the methods for extracting properties to consolidate the logic
* hReview parsing is incomplete due to issues with the php-mf2 backcompat parsing. see https://github.com/indieweb/php-mf2/issues/107

closes #18

if the photo has a location, the timezone is set on the published date

If the input URL contains a fragment, finds the DOM tree at that ID and runs the subtree through the mf2 parser.

closes #15

errors fetching the URL should not result in a 400 response

closes #9

if a property such as `in-reply-to` is an h-cite, the URL is still returned as the `in-reply-to` value, and the h-cite object is available in a different part of the response.

closes #6

* extracts mf2 post contents from pages
* implements authorship discovery to find author info for the URL