Kill off some usages of c_str.

Also changes some function params, but this is ok.
Some simplifications were also able to be made (ie. killing off strcmps with ==, etc).

Source/Core/Core/FifoPlayer/FifoDataFile.h

@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <string>
 #include <vector>
 
 #include "Common/Common.h"
@@ -68,7 +69,7 @@ public:
 	const FifoFrameInfo &GetFrame(size_t frame) const { return m_Frames[frame]; }
 	size_t GetFrameCount() { return m_Frames.size(); }
 
-	bool Save(const char *filename);
+	bool Save(const std::string& filename);
 
 	static FifoDataFile *Load(const std::string &filename, bool flagsOnly);