crash when loading models due to corrupt download

[pudrik]

There seem to be an issue with the downloader if the phone goes into sleep.
When you wake it up it shows the files as far as the download managed to get vefore the phone turned of the screen. However resuming the download will have corrupted files causing a crash when loading the models.

I guess allowing the downloads continue in the background could fix this issue

Clearing the data / reinstalling the models without allowing the phone going into sleep seem to fix the issue

Tested on Oneplus Open in normal phone mode.