build: Always build in C++11 mode.

This commit also includes update of websocketpp submodule, as the
previous version has compilation problems on OSX with XCode 6.1

Change-Id: I8c9670d0026d840838d77e610e50679ee5ede7a5
Refs: #1930, #2082
diff --git a/tests/daemon/mgmt/manager-base.cpp b/tests/daemon/mgmt/manager-base.cpp
index 58a6fd4..5d2b6c3 100644
--- a/tests/daemon/mgmt/manager-base.cpp
+++ b/tests/daemon/mgmt/manager-base.cpp
@@ -80,7 +80,7 @@
   shared_ptr<InternalFace>
   getInternalFace()
   {
-    return ndn::ptr_lib::static_pointer_cast<InternalFace>(m_face);
+    return static_pointer_cast<InternalFace>(m_face);
   }
 
   void