Error for non-UTF inputs

[giovannipizzi]

Here this is done outside the try/except:

tools-seekpath/compute/__init__.py

Line 103 in a85482a

filecontent = structurefile.read().decode("utf-8")

And therefore it crashes for non-UTF8 inputs, e.g. this CIF:
NiTe2.txt

The simplest approach is to put that line inside the next try block, at least to show a nice error message rather than a 500 error.
The second step would be to see if one can avoid decoding using directly bytes, or try some clever detection of encoding since often the weird characters are not really needed and can be ignored.

Originally reported in materialscloud-org/issues#22