Engine: properly adjust window size when buffers are resized

The engine never updates CGame's window size members when the window size is adjusted. This patch now calls CGame::SetWindowSize() when the window is resized to make sure these members are always in sync.

src/windows/id3dx.cpp

@@ -138,6 +138,7 @@ HRESULT __stdcall ResizeBuffers(IDXGISwapChain* pSwapChain, UINT nBufferCount, U
 	g_nWindowRect[1] = nHeight;
 
 	///////////////////////////////////////////////////////////////////////////////
+	g_pGame->SetWindowSize(nWidth, nHeight);
 	return s_fnResizeBuffers(pSwapChain, nBufferCount, nWidth, nHeight, dxFormat, nSwapChainFlags);
 }