About module prepend

We (irosenb and I) have added Module's "prepend" functionality to a class called AboutModulePrepend. The current test just shows that a module mixed in with the "prepend" keyword rather than with the "include" keyword will allow the overridden methods of an object mixing in the module to use the module method rather than the class method. Since this is the only added test, it would make more sense to put this in an already existing test class, like AboutModules.

We'll continue to research Module#prepend. If it has any other useful and simple functionality worth showing off to a new Ruby user, we'll update this request.

Thanks,
Stefan