Readme and sources out of sync

[ghost]

This issue is for master/examples/CoreML/ONNXLive

Apparently, in previous versions a shell script was used to download the models which is now a python script. So "./download_saved_models.sh" should be "python download_saved_models.py".

I am aware that everybody is able to change this on their own while going through the tuturial, so this issue is just for the sake of cohesiveness in the Readme.