more consistently returns HTTP 410 now

* mf2+html
* mf2+json
* feed+json
* xml
* instagram/facebook/github/xkcd

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

Grabs rel values from both HTTP headers and link tags and merges them together, and resolves any relative values. Also returns the final URL requested and the HTTP response.

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

* adds .htaccess files for apache
* adds installation instructions and nginx example
* prevent source folders from being viewed with .htaccess
* adds `index.php` in root folder in case you deploy this whole thing to a subfolder
* updates to work when installed in a subfolder

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