Paranoia commit.
- Adding the concept of a "validator" to a currency.
--- This validator is able to validate blocks and transactions in a context-sensitive manner.
--- One possibility is that this will be composed of several sub-validators.
- Adding the concept of a "block chain".
--- Need a better name, because this one's going to be misleading, big-time.
--- This is really just a mapping for identifiers, with a concept of "length".
--- It maps block <--> height and block <--> transaction(s).
--- TODO: support the concepts of "best" vs "candidate" vs "unlikely".
--- This is intended to eventually be backed by persistent storage, to overcome the current limitation that the app needs to start from scratch every time.
- Removing a lot of cheating from the Cheating class.
- Adding .ConfigureAwait(false) in many places.