add syndication reload button to the settings screen

closes #87

this allows tag values to contain spaces, which is up to your own micropub server to handle appropriately.

closes #95 and replaces #96

let's give this a shot

closes #71

* now you can enter alt text for photos. see https://www.w3.org/TR/micropub/#uploading-a-photo-with-alt-text for details
* if the note has alt text, then the request is sent as JSON instead

* adds setting to choose the property to use for the syndication targets
* all existing users default to the old value `syndicate-to`
* new users default to `mp-syndicate-to`

closes #66

closes #61

closes #62

* 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

* 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

The `#note_photo` form element is the only instance in the application
that used the attribute.

Accidents happen, you shouldn't have to refresh the entire page
to get rid of the image.

closes #36