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

main difference is the deprecated rel handling

closes #62

also expands parsing to be able to handle twitter JSON from the streaming API which is subtly different from the HTTP API.

closes #61

closes #13

closes #51

closes #57

fix for #53

use parseHTMLValue function for event description

allows the XKCD XML feeds to be parsed with the feed parser

* adds test of instagram-atom feed with individual authors per item
* dedupes atom/rss title if it's a prefix of the content

if an item has multiple URL values, return the one that is on the same domain

Treats `https://example.com` and `https://example.com/` as equivalent when comparing URLs. Closes #33

closes #32

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

according to http://microformats.org/wiki/h-entry the rsvp values should be interpreted case-insensitive

checkin data is returned embedded like author data rather than in the `refs` object

closes #35

closes #40

thanks to the new backcompat in php-mf2 0.3.2