Get rid of MSVC's __int64

Use either int64_t, uint64_t or long long and unsigned long long, defined as per C++11 standard

Minecraft.World/IslandLayer.h

@@ -5,7 +5,7 @@
 class IslandLayer : public Layer
 {
 public:
-	IslandLayer(__int64 seedMixup);
+	IslandLayer(int64_t seedMixup);
 
 	intArray getArea(int xo, int yo, int w, int h);
 };