#4901: Merges 1.8 (b2232139) into master

Currently failing one unit test for me:

Fail: .../engine/tests/ElggCoreObjectTest.php -> ElggCoreObjectTest -> testElggEntityRecursiveDisableWhenLoggedOut -> Expected false, got [Object: of ElggObject] at [.../engine/tests/ElggCoreObjectTest.php line 224]

Lots of changes here! Give it a whirl.