Remove Static Method Requirement for Handler List

[jhallbachner]

The code for retrieving a list of available handlers (currently generated by a static method in the StashHandlers class) should be refactored so it does not require a static call, possibly by moving it into the Stash object.

[tedivm]

I'm closing this out for now, as it really has to be static the way it currently works. I think we ultimately need to remove this class altogether and replace it with something else though- another issue along those lines would make sense for discussion.