moves XRay classes to `p3k\XRay` namespace

* removes the HTTP classes from this project and uses p3k-http library instead
* reorganizes the XRay classes into a psr-4 compatible folder
* moves controller autoload into -dev in preparation for turning this into a library (#17)

closes #20

skip image alt text for now

closes #34

closes #16

* closes #14
* updated readme with details of the response
* includes `url` and `code` in the response with the final URL after following redirects and the HTTP status code returned

closes #18

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