some various changes
a lot of changes
some fixes

fixed #6 and added a “via” alternative #7
tried to fix date
some php doc
typo
added support for reply-context
thanks

thanks @barnabywalters for the mf2 parser
some typos and phpdoc
Merge remote-tracking branch 'upstream/master'
bug fix for profile pictures on likes, reposts, etc

this is what originally caused #8 for me. not sure how having comment_type 'webmention' prevents the comment avatars from displaying, but this clears it, which makes them show up again.