Remove hardcoded link to personalize_form.

In fact, it's simple and predictable to always link to the user actions list.
useractions view requires only zope2.View permission
Fix the change log mess
Implement a canonical link relation viewlet to be displayed by IHtmlHeadLinks viewlet manager
this will prevent web indexers from indexing the same object more than once, improving also the way these indexers deal with images and files.

Conflicts:

	CHANGES.txt
	plone/app/layout/links/viewlets.py
Safer, more defensive, template/view name for body class via duck typing.

Fixes conflict with <body> class attribute improvement in TinyMCE.

See comment on 1c0b89ee3556b1f42e932129058c2392275e896b#commitcomment-3832049

Conflicts:
	plone/app/layout/globals/layout.py
Revert 5bbbcd9 and fix conflict with TinyMCE body class.

Oops, now I know why it was done the way it was done before,
unfortunately the test coverage that exposes that is in
Products/CMFPlone/tests/browser.txt.

Conflicts:
	plone/app/layout/globals/layout.py
Merge branch 'master' of https://github.com/plone/plone.app.layout