The PrintableDecoratorMapper is a sample DecoratorMapper that will
check to see whether 'printable=true' is supplied as a request parameter
and if so, use the specified decorator instead. The name of this decorator
should be supplied in the decorator property.
The exact 'printable=true' request criteria can be overriden with the
parameter.name and parameter.value properties.
Although this DecoratorMapper was designed for creating printable versions
of a page, it can be used for much more imaginative purposes.