(bug 44804) Automatic flipping for LTR and RTL.  Also:

* Flip using Guiders' clock metaphor, not using CSSJanus (it can't support the dynamic absolute positioning)
* Bump submodule for a CSSJanus change in it, plus the document ready reposition.
* Add documentation for this and the skin overrides.
* Minor formatting and refactoring

Change-Id: I6e5a2cf35a20dd4aec1aaf29fa2bfbaee21265ae
Merge "(bug 44804) Automatic flipping for LTR and RTL.  Also:"