By default, Mashes don't state that they respond to unset keys. This
causes unexpected behavior when you try to use a Mash with a
SimpleDelegator.
This new extension allows you create a permissive subclass of Mash that
will be fully compatible with SimpleDelegator and allow you to fully do
thunk-oriented programming with Mashes.
This comes with the trade-off of a ~19KB cache for each of these
subclasses and a ~20% performance penalty on any of those subclasses.
Michael Herold