Relative links don't work in the demo, parenthesis => %2a

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Go to demo http://pagedown.googlecode.com/hg/demo/browser/demo.html
2. Add this text to the unsanitized text box:
      "See my [About](about/) page for details."
    Example like: http://daringfireball.net/projects/markdown/syntax#link

What is the expected output? What do you see instead?
Expected the link to be to "about/", but it was to 
http://pagedown.googlecode.com/hg/demo/browser/%2aabout%2a/
Is my markdown syntax right? 

What version of the product are you using? On what operating system?

Current live web demo on current Chrome OSX.

Please provide any additional information below.

Original issue reported on code.google.com by Jamshi...@gmail.com on 22 Dec 2012 at 9:09