Use EventStreams instead of RCStream to consume RecentChange events

[ottomata]

Fixes #15

I haven't tested this with Redis or anything beyoned cocytus-input.py.

[afandian]

As I said in #15 (just for the record).
The Crossref Event Data service, for which Cocytus was a prototype, uses the new SSE stream and combs Wikipedia for references to DOIs and article landing pages that can be connected to DOIs. e.g. http://query.eventdata.crossref.org/events?rows=10&filter=source:wikipedia Details here: https://www.eventdata.crossref.org/guide/