Purge ‘using namespace std’ from header files

std::bind and boost::lambda::bind don’t mix.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

src/frontend/terminaloverlay.cc

@@ -25,6 +25,7 @@
 #include "terminaloverlay.h"
 
 using namespace Overlay;
+using std::max;
 
 bool ConditionalOverlay::start_clock( uint64_t local_frame_acked, uint64_t now, unsigned int send_interval )
 {