Force reauthentication after the token expires.

the API dropped their free tier

add syndication reload button to the settings screen

makes the login experience a bit friendlier to non-developer users

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

let's give this a shot

closes #71

* 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 #69

* 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

* 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