PeerFinder work and refactoring:

* 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.

src/ripple/algorithm/api/CycledSet.h

@@ -32,7 +32,7 @@ namespace ripple {
     container.
 */
 template <class Key,
-          class Hash = typename Key::hasher,
+          class Hash = std::hash <Key>,
           class KeyEqual = std::equal_to <Key>,
           class Allocator = std::allocator <Key> >
 class CycledSet