This gives requests for ledger data (and transaction set data)
from peers a separate job type and prioritizes it appropriately.
Previously it was lumped in with fetch packs which have a low
concurrency limit. This should improve the performance of
retrieving historical information.
Source files are moved between modules, includes changed and added,
and some code rewritten, with the goal of reducing cross-module dependencies
and eliminating cycles in the dependency graph of classes.
* Remove RippleAddress dependency in CKey_test
* ByteOrder.h, Blob.h, and strHex.h are moved to basics/. This makes
the basics/ module fully independent of other ripple sources.
* types/ is merged into protocol/. The protocol module now contains
all primitive types specific to the Ripple protocol.
* Move ErrorCodes to protocol/
* Move base_uint to basics/
* Move Base58 to crypto/
* Remove dependence on Serializer in GenerateDeterministicKey
* Eliminate unity header json.h
* Remove obsolete unity headers
* Remove unnecessary includes
