Ignore state which raises errors

[achempion]

I'm looking through the code and fund the loop cycle.

ratatouille/lib/ratatouille/runtime.ex

Line 109 in 77bf3d6

loop(%State{state | model: model, subscriptions: subscriptions})

Right now on any Exception it'll abort the window. I think user wants to get a message that something is wrong but probably we could avoid aborting the whole application and loosing all state here via loading the previous "working" state back.

Or at least allow to configure custom handler for this event.