References to "/" instead os.sep break html-muncher on jython/windows

[cadu-goncalves]

Please replace references of "/" on class Util (util.py script) by os.sep.
It will make html-muncher compatilbe with jython (http://www.jython.org/) running over windows.

Regards.

[cadu-goncalves]

In fact the same problem occurs inside class Muncher, which also uses "/" instead os.sep.