Sort out the pip install and release on PyPI

[JamesOwers]

Users shouldn't require pytorch unless they want to do experiments etc.

Dont forget warnings in scripts if things aren't installed.

Reorganise folder structure.

Will fix #111 #131

https://medium.com/@joel.barmettler/how-to-upload-your-python-package-to-pypi-65edc5fe9c56

[JamesOwers]

Started the process with #142