Project-wide consistent error handling.

Termie and I discussed a strategy for doing consistent project-wide error handling that would look something like this:

we define a central error handling mechanism "catch_exception" which is called from inside an except block that knows how to handle all the various API backends' error types, and can make determinations on whether they are passable or "fatal". If they are fatal they would be raised up to a higher-level middleware that redirects to an error page or logout ciew as necessary. If they are not fatal appropriate logging and messaging happens and the code flow is returned to the view.