Fixed all the compiler warnings, fixed depreciated screenshot function

src/Old_Map.cpp

@@ -1,4 +1,3 @@
-#pragma once
 #include <iostream>
 #include <SFML/System/Vector3.hpp>
 #include <SFML/System/Vector2.hpp>
@@ -369,4 +368,4 @@ void Old_Map::diamond_square(int stepsize, double scale) {
 		}
 	}
 
-}
+}