micropub_media_post_for_user makes a case-sensitive search for the
Location header, which fails if the location header is all lowercase.

This change uses the `headers` fields, introduced in
2b98a4548e82f1133bf62918b0106ab99a21fa29a, to find the Location header,
regardless of case.

closes #112

likes and reposts the tweet on twitter first, then sends a syndication URL in the micropub endpoint

* new route `/edit?url=` intended to be used as an edit button target, which detects the type of post and redirects to the appropriate editing interface
* implemented the edit interface for favorites

closes #68

closes #67

* shows reply context of the URL you're replying to
* autocomplete nicknames from the post when replying
* moved debug info to the settings screen to clean up the UI

fixes #47

fixes #59

* looks for a media endpoint in the micropub config
* if media endpoint is available, both the note interface and the editor will upload files to it instead of posting the photo directly
* the note interface autosaves in-progress notes in localstorage

closes #36

Quill corrects the photo rotation based on exif data since iOS tends to take landscape photos and set the rotation bit when holding it in portrait mode.

Comes up for Known which gives funky syndication-target IDs like twitter::kylewmahan.

fixes #18

closes #4

With this it is possible to post a photo note with a description, nothing
more. It doesn't move the file in the file system, just posts it from
the temp location to the users server. It also does validate for file size,
content type and max upload size and shows the errors to the user.

If everything goes according to plan the response from the users server
is shown, together with a link with the posted photos URL.