load_pdb in FFEA_pdb.py cannot handle files with ANISOU fields

[Ryan Cocking]

load_pdb() usually expects PDB files where there is a big block of lines, all beginning with the 'ATOM' field (five float columns).

However, the ‘ANISOU’ field (six int columns) is usually paired to an ATOM, so the entries go as:
ATOM
ANISOU
ATOM
ANISOU
…

which returns an invalid float error as the loader ends up reading two columns at once, which would end up with meaningless data even if it didn’t break.

I’ve made the RodSteric branch throw an error when this happens, with a polite suggestion that the user sort their own file out, but we should just make the loader skip every other line if this happens.

I’ll also add that the reader uses some rather outdated methods of reading files, e.g. f = open(), f.readlines(), etc… Holdouts from Python 2!

The offending PDB!

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