Etherpad v1.5.1

NEW: High resolution Icon
NEW: Use HTTPS for plugins.json download
NEW: Add 'last update' column
NEW: Show users and chat at the same time
NEW: Support io.js
Fix: removeAttributeOnLine now works properly
Fix: Plugin search and list
Fix: Issue where unauthed request could cause error
Fix: Privacy issue with .etherpad export
Fix: Freeze deps to improve bisectability
Fix: IE, everything. IE is so broken.
Fix: Timeslider proxy
Fix: All backend tests pass
Fix: Better support for Export into HTML
Fix: Timeslider stars
Fix: Translation update
Fix: Check filesystem if Abiword exists
Fix: Docs formatting
Fix: Move Save Revision notification to a gritter message
Fix: UeberDB MySQL Timeout issue
Fix: Indented +9 list items
Fix: Don't paste on middle click of link
SECURITY Fix: Issue where a malformed URL could cause EP to disclose installation location