There should be a way to add metadata to a page. Probably a plugin could do
this, for example:

	\[[!meta foo="bar"]]

Uses for this include:

* Setting a page title that's not tied to the filename.
* Any metadata that's generally useful on html pages.
* Maybe as an alternate way to tag a page, like linking to the tag,
  except it doesn't have to show up in the page text.
* Recording page licenses.

[[!meta link=done]]
[[!meta title="supporting metadata..."]]
[[!meta author="Joey Hess"]]
[[!meta link="foo.css" rel="stylesheet" type="text/css"]]

[[todo/done]]
