[core] Signal: implementation adapted to C++0x style
[core] Signal: implementation adapted to C++0x style

xzero/x0,christianparpart/x0,xzero/x0,christianparpart/x0,christianparpart/x0,christianparpart/x0,christianparpart/x0,christianparpart/x0,christianparpart/x0,xzero/x0,xzero/x0,xzero/x0,xzero/x0