Peer shutting down while waiting for transaction: marking cheques as cashed

[Eknir]

It is possible that the node shuts down, while it is waiting for a transaction to be executed.
Perhaps we should keep a list of cheques and mark them as cashed / uncashed.
Then, when the node boots up again, he verifies his uncashed cheques and if, according to his preferences (which is now: always cash a cheque directly), he wants to submit a cheque which is marked as not submitted, he will first look in the blockchain whether this cheque is really not submitted.

[ralph-pichler]

Issue description should be updated to only refer to cashing.

[Eknir]

@ralph-pichler , what is the status on this PR?

[ralph-pichler]

While implemented a bit differently, the general idea behind this will be implemented in #2089 (which will probably be split into smaller PRs).

If you want, we can also close this is in favour of #2005.