Design.from_scadnano_file has no option to suppress warnings for duplicate strand names

[cgevans]

Design.write_scadnano_file has the warn_duplicate_strand_names argument that suppresses warnings about duplicate strand names. Design.read_scadnano_file does not, which causes problems for tile systems.

I actually wonder whether it might make sense to have the duplicate strand name check function check to see if the two identically-named strands could be copies of the same strand, eg, have the same sequence, and not warn if that's the case? This would mostly remove the need for the warn_duplicate_strand_names=False possibility for tile systems.