TorConnect: handle switching from Bootstrapped to Configuring state
!721 (merged) is going to enable switching from the "Bootstrapped" state to the "Configuring" state when the underlying tor process exits after bootstrapping has first succeeded. The idea is that we can re-bootstrap with the new tor process.
This could probably do with some general testing to see how well we recover in this case.
We also have some UI elements that assumed we would never leave the "Bootstrapped" state once it was reached. We should change them now that this assumption is broken.