more consistently returns HTTP 410 now

This adds a new property, "meta", which includes alt text and has room to include additional properties later.

closes #85

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

returns a new property `post-type` next to `type`

closes #25

adds script to refresh the downloaded instagram data for the tests as well

instagram seems to have rolled out the `graphql` key everywhere now

uses the video's poster frame as the photo if any of the multi-post images are videos

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)

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