Add real error handling

[apmwebdev]

Currently, the app doesn't do much with errors except maybe log something to the console. There should be better error handling so that, at the very least, some sort of feedback is presented to the user and the app doesn't just fail silently. Implementing a universal error handler that presents a toast or something would likely be a good idea. There should also be the ability to pass a callback to the error handler for any additional logic that's needed for specific failures in the app.