Refactor beast::asio:

* New tools for completion handlers:
  - wrap_handler provides composed io_service execution guarantees.
  - bind_handler rebinds arguments to handlers.
  - shared_handler type-erases any completion handler.
  - buffer_sequence type-erases templated BufferSequences
  - abstract_socket replaces Socket
  - socket_wrapper replaces SocketWrapper
  - beast::asio placeholders to work with std::bind

* Removed obsolete classes and functions
  - AbstractHandler
  - ComposedAsyncOperation
  - SharedFunction
  - SharedHandler
  - SharedHandlerAllocator
  - SharedHandlerPtr
  - SharedHandlerType
  - SocketBase
  - SocketWrapperStrand
  - wrapHandler

* Refactored classes to use new tools
  - abstract_socket
  - socket_wrapper
  - HandshakeDetector
  - HttpClientType

* Miscellanous tidying
  - socket classes moved to beast::asio namespace
  - beast asio files provide their own namespace declaration.
  - Fix IsCallPossible conflicting template parameter name
  - Use <boost/get_pointer.hpp> for C++11 compatibility.
  - Remove extraneous include path from build environment.

src/ripple_core/functional/Job.cpp

@@ -54,7 +54,7 @@ JobType Job::getType () const
 
 CancelCallback Job::getCancelCallback () const
 {
-    bassert (! m_cancelCallback.empty());
+    bassert (m_cancelCallback);
     return m_cancelCallback;
 }
 
@@ -65,7 +65,7 @@ Job::clock_type::time_point const& Job::queue_time () const
 
 bool Job::shouldCancel () const
 {
-    if (! m_cancelCallback.empty ())
+    if (m_cancelCallback)
         return m_cancelCallback ();
     return false;
 }

src/ripple_core/functional/JobQueue.cpp

@@ -22,8 +22,8 @@
 #include "JobTypeInfo.h"
 #include "JobTypeData.h"
 
-#include "../beast/beast/cxx14/memory.h"
-#include "beast/beast/chrono/chrono_util.h"
+#include "../../beast/beast/cxx14/memory.h"
+#include "../../beast/beast/chrono/chrono_util.h"
 
 #include <chrono>
 

src/ripple_core/ripple_core.cpp

@@ -25,7 +25,7 @@
 #include <map>
 #include <set>
 
-#include "beast/modules/beast_core/system/BeforeBoost.h"
+#include "../beast/modules/beast_core/system/BeforeBoost.h"
 #include <boost/algorithm/string.hpp>
 #include <boost/foreach.hpp>
 

src/ripple_core/ripple_core.h

@@ -23,8 +23,8 @@
 #include "../ripple_basics/ripple_basics.h"
 #include "../ripple_data/ripple_data.h"
 
-#include "beast/beast/http/URL.h" // for Config
-#include "beast/beast/Insight.h"
+#include "../beast/beast/http/URL.h" // for Config
+#include "../beast/beast/Insight.h"
 
 #include "../ripple/resource/api/LegacyFees.h"