Restructure: take wrappers and I/O from partialwrap, take function directory from JAMS

v2.0 (Jun 2020)

- Use package partialwrap in docstrings and documentation.
- Remove utils directory: tee.py is now directly in pyeee directory.
- Sync const and functions of JAMS package.
- Generalise structure of setup.py.
- Build only only on TravisCI because tests are/were only done on Linux.