Fix public member names of RPC::Context.

Conflicts:
	src/ripple/rpc/handlers/AccountTx.cpp
	src/ripple/rpc/handlers/AccountTxOld.cpp
	src/ripple/rpc/handlers/Ledger.cpp
	src/ripple/rpc/handlers/LedgerData.cpp
	src/ripple/rpc/handlers/RipplePathFind.cpp
	src/ripple/rpc/handlers/ServerInfo.cpp
	src/ripple/rpc/handlers/ServerState.cpp
	src/ripple/rpc/handlers/Submit.cpp
	src/ripple/rpc/handlers/Subscribe.cpp
	src/ripple/rpc/handlers/TxHistory.cpp
	src/ripple/rpc/handlers/Unsubscribe.cpp
	src/ripple/rpc/impl/Context.h
Clean up Pathfinder.

* Restrict to 80-columns and other style cleanups.
* Make pathfinding a free function and hide the class Pathfinder.
* Split off unrelated utility functions into separate files.

Conflicts:
	src/ripple/rpc/handlers/RipplePathFind.cpp
Fix pathfinding with multiple issuers for one currency (RIPD-618).

* Allow pathfinding requests where the starting currency may have
  multiple issuers.

* Cache paths over all issuers to avoid repeating work.

* Clear the ledger checkpoint in one retry case.

* Add an additional node at the front of paths when the starting issuer
  is not the source account.
Remove unused isXRP(Issue) function.
Fix compilation errors in RPC/RipplePathFind.cpp
Adjust SSL context generation for Server:
The creation of self-signed certificates slows down the command
line client when launched repeatedly during unit test.
* Contexts are no longer generated for the command line client
* A port with no secure protocols generates an empty context
Add missing includes.
Refactor the structure of source files:
* New src/ripple/crypto and src/ripple/protocol directories
* Merged src/ripple/common into src/ripple/basics
* Move resource/api files up a level
* Add headers for "include what you use"
* Normalized include guards
* Renamed to JsonFields.h
* Remove obsolete files
* Remove net.h unity header
* Remove resource.h unity header
* Removed some deprecated unity includes
Update freeze test for moved TxFlags.h
Add missing include needed for std::bad_cast in LexicalCast.h
Add weak_fn
Remove obsolete get_pointer
Throw if rippled.cfg is missing a [server] section
Better logging when opening Server ports.
Overlay improvements and bug fixes:
PeerImp::detach had a default argument graceful=true which did not
correctly close the socket and cause the Overlay to often hang on exit.
The logging for Overlay and Peers has been reworked. All the socket activity
is logged to Peers while protocol activity goes to Protocol. Every log line
is prefixed by a small integer ID unique to the connection.
* Removed graceful PeerImp::detach option
* Peer and Protocol log message handle respective types of logging
* Log messages prefixed with peer unique integer
* Prevent call to timer ancel from throwing an exception
Fix weak_fn unit test.
Fix account_lines, account_offers and book_offers result (RIPD-682):
The RPC account_lines and account_offers commands respond with the correct
ledger info. account_offers, account_lines and book_offers allow admins
unlimited size on the limit param. Specifying a negative value on limit clamps
to the minimum value allowed. Incorrect types for limit are correctly reported
in the result.
Add rfc2616::parse_csv
Make ci_equal a function
Add operator<< for basic_streambuf