Catch and translate exceptions

[dagit]

As part of our effort to not expose users to the details of our dependencies we should translate exceptions to something that is meaningful to users of our API.

[dagit]

While this issue documents ideal behavior of our library, it's hard to figure out all the exceptions that can be thrown (and will change whenever our dependencies change). As such, I'm removing this from the public release milestone. I still want to improve on our exception handling but I don't want it to block our first public announcement.