Switch to ep_author_neat2

Summary:
The ep_author_neat plugin isn't maintained anymore,
and doesn't work on latest Etherpad up-to-come release.

The ep_author_neat2 plugin works fine.

Test Plan: Tested on pad.nasqueron.org

Reviewers: dereckson

Reviewed By: dereckson

Differential Revision: https://devcentral.nasqueron.org/D2768