Setup graceful error handling

[jswent]

[jswent]

@james-d-mitchell lets set for Wednesday to decide on a plan for error handling. I did some reading today and it looks like we have a few choices for how to proceed, which we'll have to decide on what balance of UX/performance/verbosity we want to strike.

[jswent]

Begun to address in #18

[jswent]

Closing this as addressed in #18