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 ripple::Account, ripple::Currency, ripple::Directory.

* New tagged uint types.
* Extract to_string functions from header to hide dependencies.
* New IssuedCurrency struct.
* Include what you use and C++11 for cleanups.
Get rid of uint160 in favor of Currency, Account and NodeID.

* New uint160 tagged type NodeID.
* Categorize *all* non-generic instances of uint160.
* Move conversions to and from strings to central .h file.
* Extract macro constants to be functions.
* Get rid of constructors and comparators between tagged uint types.
* New base_uint::copyFrom() allows explicit copying between any uint types
  of the same size.
* And lots of incidental cleaning and removal of unused code.
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Responses to review.