mio_dataset.py loading data from /opt

[hashimSharif]

https://github.com/IBM/mini-era/blob/master/cv/CNN_MIO/mio_dataset.py#L8

The script loads data files from a system-specific path.

[jdwellman]

Good point; could maybe have some auto-configuration or something, but I'm not 100% sure how best to address this. This should probably address this in the README and either specify the location one should put the MIO dataset (to conform to above through that seems overly restrictive) or make the user edit the script, or set an environment variable (used in the script) that points to the MIO dataset (which I think IS listed as a requirement?).