Example data download seems to hang

[jbednar]

The python library calls used to download the sample data give no indication of progress, and can take many tens of minutes, making it completely unclear whether it will complete successfully. We used Python to do this so that it would work across platforms, but maybe we should first try wget or curl and only then fall back to Python's stdlib if those are not available.

[brendancol]

stale issue...data download script has now changed