Export pagetitle, titlepage, linkpage.
* Allow for underscores to appear in page titles, if encoded appropriately (__95__) in filenames. Previously, all underscores were replaced with spaces. Thanks, Enrico Zini for noticing that bug.
dirname, basename, bestlink, linkify, pagetitle, titlepage. * Allow links of the form [[some page|page]], with whitespace in the link text.