Upgrade to C++-14:

* Remove cxx14 compatibility layer from ripple
  * Update travis to clang 3.6 and drop gcc 4.8
  * Remove unneeded beast CXX14 defines
  * Do not run clang build with gdb with travis
  * Update circle ci to clang 3.6 & gcc-5
  * Don't run rippled in gdb, clang builds crash gdb
  * Staticly link libstdc++, boost, ssl, & protobuf
  * Support builds on ubuntu 15.10

src/ripple/nodestore/backend/NullFactory.cpp

@@ -20,7 +20,7 @@
 #include <BeastConfig.h>
 #include <ripple/nodestore/Factory.h>
 #include <ripple/nodestore/Manager.h>
-#include <beast/cxx14/memory.h> // <memory>
+#include <memory>
 
 namespace ripple {
 namespace NodeStore {