Refs #4970 prevent Firefox from adding files to TinyMCE editor
Fixes #4802 notifications sent when status is newly set to published
added session to service provider
using ElggSession in sessions lib
replaced calls to session global with ElggSession in engine
session_ functions replaced by session object
added storage and tests
deprecated global $SESSION
not running PHP session native storage tests on Travis
pulled more session code into ElggSession
Fixes #5182 - Adds file_exists results cache in ElggViewService
moved session db code into class
Fix activity page titles
Fixes #4913: Admins can view any user's activity stream
Fixes #3481. Data moved to GUIDs instead of dates.
Migrated to Elgg_EntityDirLocator. Updated simpleTest tests.
Fixed upgrade for data dir.
made the event more general for future support of objects with draft/publish status
Merge pull request #5131 from cash/blog_notifications

Fixes #4802 notifications sent when status is newly set to published
don't allow comments on draft blog posts