Tests: Written manual one for ticket.
Tests: Written one which checks whether iterator don't go beyond the sandbox.
Preventing iterator against getting out of editor DOM.
Docs: Improved.
Postreview changes.
Added private setEndContainer method in range.
Refactoring: getNextSourceNode in iterator is private now.
Tests: Added simple ones for setting containers in a range.
Added @since tags.
Tests: Updated test which fails.
Simplified validation check and fix for IE8.
Moved test files to more standard place.
Tests: Improved texts in manual tests a bit.
Improved docs.
Changelog entry.
Merge branch 't/12484b'
Tests: Added tcs for filtering custom tags.
Don not throw when filtering custom elements.

Added a check whether "DTD[ parent.name ]" exists, before accessing "DTD[ parent.name ] && DTD[ parent.name ][ child.name ]".
Otherwise, if you have some exotic tag in your HTML, the scripts would throw an exception.
Handle custom elements in other places too.
Changelog entry.