Integration of the Sphere with Maximum Determinant Points

[PaulWAyers]

It came up yesterday in discussions whether there might be alternatives to spherical designs and Lebedev-style quadrature on the sphere. An alternative, with nonequal but always positive weights, is the maximum determinant stategy.

Up to a degree of 200, the points/weights are available here.

Incidentally, the same web page has one spherical design beyond what we have right now, for degree 325.

This isn't an especially high priority, but is a nice starter issue and something fun to play with.

[Ali-Tehrani]

Note that when someone adds the new grid, they should also change MANIFEST.in to include the data files when installing and to also change the tests in test_atomgrid.py and test_molgrid.py. This can be easily done since it uses @pytest.mark.parameterize