Accept an available alternative residue coordinates if there is no other alternative

[DrrDom]

Chimera during protein curation selects one of alternative coordinates if there are several. However, when Chimera saves the protein the IDs of alternative coordinates are kept. This triggers meeko to ask a user to choose one of alternative coordinate sets. However, there is actually only one set of coordinates for an atom. It may be convenient to check if there is only one alternative coordinate set for an atom and choose it automatically. This should improve user experience.

It works only if explicitly specify which coordinate set to choose:

mk_prepare_receptor.py -i 3ral.pdb -o 3ral -p --wanted_altloc A:118=A,A:177=B,A:232=A

3ral.pdb.txt

[diogomart]

Good idea. We'll do.