Should flattenError really exist? #10

Seems like if we're just throwing our own errors and have the errors export that we should be able to handle the flattening and property management a bit more cleanly. Wondering if we need to dig into this method and the error classes (and maybe other error handler code in Jeopardy) and have a more comprehensive plan. Seems like flattenError (which used to be streamlineError) is part of just some hacky troubleshooting and a better solution exists.