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/AddIslandLayer.h

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