Add **Web platform with Emscripten**

Source/Engine/Platform/Web/WebDefines.h

@@ -0,0 +1,30 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#pragma once
+
+#if PLATFORM_WEB
+
+#include "../Unix/UnixDefines.h"
+
+// Platform description
+#define PLATFORM_TYPE PlatformType::Web
+#define PLATFORM_64BITS 0
+#define PLATFORM_ARCH ArchitectureType::x86
+#define PLATFORM_CACHE_LINE_SIZE 64
+#define PLATFORM_DEBUG_BREAK 
+#define PLATFORM_OUT_OF_MEMORY_BUFFER_SIZE 0
+
+// Configure graphics
+#define GPU_ALLOW_TESSELLATION_SHADERS 0
+#define GPU_ALLOW_GEOMETRY_SHADERS 0
+#define GPU_ALLOW_PROFILE_EVENTS 0
+
+// Threading is optional
+#ifdef __EMSCRIPTEN_PTHREADS__
+#define PLATFORM_THREADS_LIMIT 4
+#else
+#define PLATFORM_THREADS_LIMIT 1
+#define GPU_ENABLE_ASYNC_RESOURCES_CREATION 0
+#endif
+
+#endif