editpage escaping fixes

editpage escaping fixes

* The editpage form now uses the raw page name, not the page title, in its
  'page' cgi parameter. Using the title was ambiguous and made it
  impossible to tell between some pages, like "foo/bar" and "foo__47__bar",
  sometimes causing the wrong page to be edited.
* This change means that some edit links need to be updated.
  Force a rebuild on upgrade to this version.
* Above change also allowed really fixing escaped slashes from the blogpost
  form.