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/daemon/face/face.cpp b/daemon/face/face.cpp
index f3757ff..7d3c1b7 100644
--- a/daemon/face/face.cpp
+++ b/daemon/face/face.cpp
@@ -36,10 +36,10 @@
   , m_isOnDemand(false)
   , m_isFailed(false)
 {
-  onReceiveInterest += bind(&PacketCounter::operator++, &m_counters.getNInInterests());
-  onReceiveData     += bind(&PacketCounter::operator++, &m_counters.getNInDatas());
-  onSendInterest    += bind(&PacketCounter::operator++, &m_counters.getNOutInterests());
-  onSendData        += bind(&PacketCounter::operator++, &m_counters.getNOutDatas());
+  onReceiveInterest += [this](const ndn::Interest&) { ++m_counters.getNInInterests(); };
+  onReceiveData     += [this](const ndn::Data&) {     ++m_counters.getNInDatas(); };
+  onSendInterest    += [this](const ndn::Interest&) { ++m_counters.getNOutInterests(); };
+  onSendData        += [this](const ndn::Data&) {     ++m_counters.getNOutDatas(); };
 }
 
 Face::~Face()