Use libpng for saving images.

TODO: Needs threading done similiar to OGL backend.
Fixes issue 6779.

Source/Core/VideoBackends/D3D/Src/TextureCache.cpp

@@ -62,7 +62,7 @@ bool TextureCache::TCacheEntry::Save(const char filename[], unsigned int level)
 		HRESULT hr = D3D::context->Map(pNewTexture, 0, D3D11_MAP_READ_WRITE, 0, &map);
 		if (SUCCEEDED(hr))
 		{
-			hr = D3D::TextureToPng(map, UTF8ToUTF16(filename).c_str(), desc.Width, desc.Height);
+			hr = D3D::TextureToPng(map, filename, desc.Width, desc.Height);
 			D3D::context->Unmap(pNewTexture, 0);
 		}
 		SAFE_RELEASE(pNewTexture);