[pmwiki-users] 2.2.0: add Site.SiteHeader and Site.SiteFooter

[The Editor]

Being as it's easy enough to add a skin section for something like an
allgroupheader, I'm not really convinced it needs to be in core. Seems
it should go in the skins, like it already does.

Just my 2 cents. I already have something like this in my skin so it's
unlikely I would use it either way. Seems one of the PmWiki philosophy
points should go here.

Cheers,
Dan