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/InputStream.h

@@ -11,7 +11,7 @@ public:
 	virtual int read(byteArray b) = 0;
 	virtual int read(byteArray b, unsigned int offset, unsigned int length) = 0;
 	virtual void close() = 0;
-	virtual __int64 skip(__int64 n) = 0;
+	virtual int64_t skip(int64_t n) = 0;
 
 	static InputStream *getResourceAsStream(const wstring &fileName);
 };