Core: Pass string by const reference in SaveScreenShot

Source/Core/Core/Core.cpp

@@ -678,7 +678,7 @@ void SaveScreenShot()
 		SetState(CORE_RUN);
 }
 
-void SaveScreenShot(const std::string name)
+void SaveScreenShot(const std::string& name)
 {
 	const bool bPaused = (GetState() == CORE_PAUSE);
 

Source/Core/Core/Core.h

@@ -52,7 +52,7 @@ void SetState(EState _State);
 EState GetState();
 
 void SaveScreenShot();
-void SaveScreenShot(std::string name);
+void SaveScreenShot(const std::string& name);
 
 void Callback_WiimoteInterruptChannel(int _number, u16 _channelID, const void* _pData, u32 _Size);