Pedestal client's exception catching code makes it significantly more difficult to debug in-browser errors

Presently exceptions raised during pedestal-app's dataflow execution are caught and printed as simple errors. This is undesirable because it stops quite advanced built-in JS development tools like Chrome's Developer Tools from providing their own exception functionality (linked stack traces, stack inspection, etc.).

We should consider think about and consider *not* catching this errors and allowing them to bubble up to user-space.