Improve Journal logging framework:
* Allow partition log levels to be adjusted
* Cleanups
SHAMap refactoring:
* Rename SHAMapNode to SHAMapNodeID.
* Cleanups
Ledger loading cleanups:
* Fix close time settings for ledger load
* More info in ledger_request and inbound ledger JSON replies
New types Account, Currency, Directory:
* New tagged uint types.
* Extract to_string functions from header to hide dependencies.
* Include what you use and C++11 for cleanups.
Basic hygiene upgrade.
Make SHAMapNodeID a member instead of a base.