Fixed parameter type mismatch in StreamReader.

code/StreamReader.h

@@ -193,7 +193,7 @@ public:
 
 	// ---------------------------------------------------------------------
 	/** Increase the file pointer (relative seeking)  */
-	void IncPtr(int plus)	{
+	void IncPtr(size_t plus)	{
 		current += plus;
 		if (current > limit) {
 			throw DeadlyImportError("End of file or read limit was reached");