All CLI apps that use clap (in other words, except for bench-streamer)
can use crate_version! to take the version from Cargo.toml.
This change addresses #700.
* add recover_ledger() to deal with expected common ledger corruptions
* add verify_ledger() for future use cases (ledger-tool)
* increase ledger testing
* allow replicate stage to run without a ledger
* ledger-tool to output valid json
Kazuyoshi Kato
Michael Vines
Rob Walker