Dynamic type interface.
$Id: Dynamic.py,v 1.2 2003/01/06 20:43:40 yuppie Exp $
General interface for dynamic items.
This method returns the path to an object's icon. It is used in the folder_contents view to generate an appropriate icon for the items found in the folder.
If the content item does not define an attribute named "icon" this method will return the path "/misc_/dtmldoc.gif", which is the icon used for DTML Documents.
relative_to_portal is true, return only the portion of
the icon's URL which finds it "within" the portal; otherwise,
return it as an absolute URL.