Missing bravais lattice symmetries and tolerance factor problem

This is a two sided problem of the high-symmetry points method for the band structure and the Brillouin zone. As an example of what I mean, please check out the following picture:

This is done for Si2. As you can see, the high-symmetry points cannot be recognize.

After digging up a bit, I saw a couple of problems in the band_structure.py normalizer. Please, feel free to correct me if I am wrong or I overlooked something:

1. Some symmetries are not addressed in BandStructureNormalizer:get_special_points method: there should be 14 Bravais lattices (see e.g. Wikipedia or the paper by Setyawana and Curtarolo) and there are only 6 defined for the high-symmetry points. As said in the method: "This is copied from the VASP parser", so it essentially fails for all the other electronic codes I checked.
2. I think the tolerance factor should be relaxed to 0.01 or 0.001 Å (right now it is 0.0001 Å, which might be a bit restrictive when capturing the correct symmetry).

The point 2. is easy to implement. The point 1. is much more involved. @mscheidg @lucamghi @ndaelman : wouldn't be better to simply comment out these assertions and come up with a more generalized check later on? As I see it, having the high-symmetry points well captured is more important right now that sanity checks on the fine details of the structure.

Let me know what you think, please.

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In the example above for Si2, the bravais_lattice is 'cF' which is addressed by the normalizer, but the assertions are failing because the three cubic directions difer by 4 ⋅ 10^-4 (which is more than 0.0001, of course).