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

update to "create" scope by default, but allow the user to choose "post" as a fallback. also updates indieauth/client to 0.2 for json support.

closes #67

* 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

allows backdating and future-dating posts

* 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 #9

fixes #54

- ?me=.. on homepage redirects to auth
- ?dontask=1 skips confirmation questions
- "reply" and other parameters are transferred across login

* 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

* it sometimes confuses web servers to have a folder named "editor" while also serving routes with the same name
* dropped appcache stuff since it wasn't working super well
* add nginx config to the readme