* Allow pagetemplate plugins to override *anything* in the template.
* Add a meta plugin, which allows specifying various metadata about pages,
like license and author. It also allows for inserting html link and meta
tags into html, overriding the title, and adding hidden WikiLinks, which
can be useful when using link-based globbing for page categorisation.
* Remove preprocessor directives from inlined pages.
* Allow simple preprocessor directive values to be specified w/o quotes.
* When inlining a page in another one, links from the inlined page are now
expanded the same as they are when rendering the inlined page as a
standalone page. So rather than being expanded from the POV of the
inlining page, they are expanded from the POV of the inlined page.
For example, a link from blog/foo to "bar" will now link to blog/bar
if it exists. Previously this needed to be a link explicitly to
"blog/bar"; such links will also continue to work.
(This was slightly complex to do as the link still has to be constructed
relative to the inlining page.)