Check network state for file download?

[peteruithoven]

Currently when the WiFi-Box is in accesspoint mode and d3dapi/update/status is requested it returns the following error: incorrectly formatted line in index file (line 1). This is caused by it receiving our 404 page.
We should probably add a network state check to our fileDownload methods.
Also see: Doodle3D/doodle3d-client#263