This PR lets the code use the Human3.6M data as provided from http://vision.imar.ro/human3.6m/filebrowser.php. This is important because their license does now allow for data redistribution, and ensures that people are getting the data from the official source.
We also fix a series of warnings for tensorflow 1.x.
We are using cdflib to read cdf files, which requires Python 3.5+, so the code now requires Python 3.5+ to run as well
cdflibto readcdffiles, which requires Python 3.5+, so the code now requires Python 3.5+ to run as well