* Use nullptr (C++11) instead of NULL.
* Put each file into its own namespace declaration.
* Remove "using namespace" directives and add scope qualifiers.
* Control when beast's implementation of std::equal (C++14) is used.
* Tidy up some const declarations.
Conflicts:
src/ripple_app/shamap/SHAMapSync.cpp
src/ripple_app/tx/TransactionEngine.cpp
* Implement PeerFinder business logic.
* Support fixed peers (including DNS support).
* Add journal support to Peer and Peers.
* Refactor PeerDoor support.
* Tidy up Peers and eliminate connection functionality and timers.
* Refactor Peer interface and add journal support.
* Allow construction of incoming Peer using an existing socket.
* Remove TESTNET support.
* Allow connections from/to cluster peers without consuming slots
* Misc. cleanups.
