Fixes #4612 returning null when a private setting does not exist
Fixes #4734 adds plugin hook for detecting mime type
Fixes #5460 deprecates Frienable interface for ElggGroup
Refs #5460 added missing method name to deprecation notice
Fixes #5422 fixes tag processing for file plugin
Fixes #5441 deprecates the entity caching functions
Fixes #5419 adds tests for enabling/disabling annotations and fixes bug with deleting disabled annotations when deleting an entity
Merge pull request #5427 from cash/enabled_annotations

Fixes #5418 adds enabled clause for annotations
Merge branch '1.8'

Conflicts:
	engine/classes/Elgg/AttributeLoader.php
	engine/lib/entities.php
added a function for enabling an entity so devs don't need to do the show hidden status dance
cleaned up entity caching code a little
basic site notifications
moved view code out of widgets service
default widgets should be in its own class so pulled out for now
tweaked the widgets service API
Fixes #4195 widgets can set their titles now - need ajax hook to pass title back
Fixes #4529 adds ajax plugin hook
Refs #4195 updating title in widget when saved
cleaned up some query formatting in users lib
Fixes #5402 fixes session wrapping