- escape & in urls (also clean up cgi url generation)
- since markdown wraps inlined pages in <p></p>, close and re-open
the paragraph tags when generating the embedded html
- added XHTML 1.0 doctypes to templates
- fixed <hr /> and <br /> in templates
- add an alt attribute to inline images, based on the WikiLink to the
image. Allows things like [[my_image|img.png]] to customise alt text.