Clients will use this API to get only changes to the Reading Lists and the entries within Reading Lists.

This is important for updating mobile clients that are maintaining local copies of the Reading Lists.

Clients will be expected to pass a date of when they last synced. The server is expected to only return changes since the date passed.

API should be of the form:
GET /lists/reading/changes/since/{date}: gets all lists and entries which changed since the given date (for device sync). Returns a marker for deleted lists/entries as well.

The format of the response is still under discussion here, but will be expected to return the following information:

Reading Lists added, updated, reordered, and deleted.
Reading List Entries added, updated, reordered, and deleted.