[Biopython-dev] pull request: Handle MMCIF with multiple models (closes 2943)

[Lenna Peterson]

I've implemented the parser changes (written by Paul Bathen; see bug
report) to allow the MMCIF parser to handle multiple models.

Models are now accessed by a string key of their model number, rather
than an arbitrary index (structure['1'] versus structure[0]).

I updated the MMCIF unit test for the new model access method and
added a test file with multiple models.

I'm not sure if there is documentation to be updated re: accessing the models.

issue: https://redmine.open-bio.org/issues/2943
pull request: https://github.com/biopython/biopython/pull/34

- Lenna