util: Replace boost::signals2 with std::function

src/qt/splashscreen.cpp

@@ -14,8 +14,8 @@
 #include <interfaces/handler.h>
 #include <interfaces/node.h>
 #include <interfaces/wallet.h>
-#include <util.h>
 #include <ui_interface.h>
+#include <util.h>
 #include <version.h>
 
 #include <QApplication>
@@ -24,6 +24,8 @@
 #include <QPainter>
 #include <QRadialGradient>
 
+#include <boost/bind.hpp>
+
 SplashScreen::SplashScreen(interfaces::Node& node, Qt::WindowFlags f, const NetworkStyle *networkStyle) :
     QWidget(0, f), curAlignment(0), m_node(node)
 {