* Update some docu & messages
* Remove cruft from the ledger modules
* Must not overwrite genesis data on an initialised database
why:
This will overwrite the global state of the Aristo single state DB.
Otherwise resuming at the last synced state becomes impossible.
* Provide latest block number from journal
why:
This relates the global state of the DB directly to the corresponding
block number.
* Implemented unit test providing DB pre-load and resume
* Provide TDD/debug facility for inspecting `persistBlocks()` working
detail:
+ Make sure that the last block of a test sample is the first batch
item in `persistBlocks()`.
+ Additionally, allow `AccountsCache` API tracing by setting the flag
`extraTraceMessages = true` in the file `accounts_cache.nim`
* Overload AccountsCache by abstraction wrapper
details:
Can facilitate CoreDb API switch, details in `ledger/README.md`.
Jordan Hrycaj