Fix issue with multiple suffixes and capitalization

As mentioned in #14, when the nameparser is passed a name like "SAHNI, ARU MD PHD", the suffix property is joined by a comma and a space. When `capitalize()` is called, the `HumanName.suffix` property is only split on space, resulting in trailing commas in the first n-1 `suffix_list` entries.

fixes #14
Merge pull request #15 from arusahni/patch-1

Fix issue with multiple suffixes and capitalization