Changelog entry.
Merge branch 't/12168' into major
Added CKCONSOLE.addEventPanel.
Added editor.dragstart, editor.drop, editor.dragend events.
Added docs.
Let user manipulate drag and drop ranges on drop event.
Catch exception from setData when setting ID.
Tests: Check drop event in tests.
Added comment about dragRange and tests for manipulating drag and drop range.
Do not need to preventDefault manually in the dragstart. Tests: dragstart and dragend fire and cancel.
Tests: Fixed: test change drag and drop range on drop.
Tests: added cancel drop test.
Tests: Set and get custom data in various events.
Tests: fixed tests on IE and Firefox.
Texts: improved tests, made them green on IE and Safari.
Tests: move asserts to the finish function and reduce number of wait/resume.