Sumo

Added Latimer-Munro high-symmetry k-point paths. (kavanase)

Fixed typo in ``sumo-bandplot``.

- Support is added for orbital-projected DOS plots from CASTEP. (zhubonan)

- The binary parser is implemented and maintained in a separate
library castepxbin. This is maintained by Bonan Zhu, available on
PyPI and pinned to a specific version in the Sumo setup.py.

Enhancements:

- ``normalise`` option added to ``bandplot`` to control the normalisation of orbital
projections. The default has been changed from ``select`` to ``all``, meaning that
the size of projections is normalised against the sum of all other projections
at that band and k-point. (utf)

Enhancements:

- Band structure grid lines can now be customised using a matplotlib
style sheet.

Sumo is now python 3.6+ only.

Additional bug fixes:

- Fix band structure interpolation with small branches (kavanase)
- Update pymatgen version requirement.

New testing and release framework.