Only recent authors can publish a collab doc

Only users who recently editted a collaborative document can publish it.
This should avoid situations where a user who is only viewing a document
triggers a publication under his name even if he did not make any
changes himself.
Fixed up failing unit tests for publishing collaborative documents
Merged master into simong/collabdocs-recent-authors
Merged master into simong/collabdocs-recent-authors
Merge oaeproject/master into collabdocs-recent-authors
Add which etherpad server is failing in error logs
Merged master into simong/collabdocs-recent-authors
Publishing collaborative documents happens by responding to MQ messages

We’re no longer publishing collab docs through the REST api. Etherpad
will send OAE a message (via RabbitMQ) whenever a user leaves the pad
and made any edits.
Fix for failing collaborative doc preview test
Code / jsdoc cleanup
Emitting an `editedCollabdoc` event when a user editted a collaborative
document that did not generate in a new revision. This also triggers an
activity for that user and pad.
Asserting only 1 revision gets created
Merge branch 'collabdocs-recent-authors' of https://github.com/simong/Hilary into collabdocs-recent-authors
Minor documentation follow-up
Reduce size of email log messages
Count `log().error` calls with the Telemetry API

The log().error function is now wrapped so the number of times it gets
called (and from where) can be tracked through the Telemetry API. This
will allow us to put Nagios checks in place that measure error rates.

In the future statsd hooks could be put in place as well.
Merge branch 'restdoc-config' of https://github.com/sathomas/Hilary into restdoc-config
Follow up on configuration REST documentation
Updating README instructions to Cassandra 2.0.x
Update Cassandra version number