Reduce scope of RPC locks and general cleanup (RIPD-458)
Further documentation improvements to Ledger Consensus.
Use std::atomic
Make CBase58Data/RippleAddress movable (RIPD-428):
This significantly increases the performance in returning
these types from factory functions.
Refactor RippleCalc:
* Rationalize method and filenames, move to subdirectory.
* Use Issue in Node.
* Restrict access to PathState variables.
* Line length and readability cleanups.
* New PathCursor stores path calculation data during rippleCalc.
* Extract methods PathCursor::node(), PathCursor::previousNode()
  and RippleCalc::addPath
More fixes to VSProject sorting algorithm
HTTP support improvements:
* RFC2616 compliance
* Case insensitive equality, inequality operators for strings
* Improvements to message_parser
* Tidy up HTTP method enumeration
* boost::asio buffer helpers
HTTP handshake in peer protocol (RIPD-351):
* New I/O paths for client and server role
* New handshake_analyzer detects the peer protocol
* New basic_message class for parsing and storing HTTP messages
* Conditional compilation for selective feature enabling.