Reverted templates back to checking author object, since a None object is possible. Name could be checked for blank if required
ATOM spec states an author element should be provided, so passes a blank name if not specified
Updated unit test
An author is needed, but was defaults to OS user, or 'John Doe'. If a blank author is provided, it generated authors/.html file, and templates display just "by "
Updated generators.py and templates to ignore Authors objects which have a blank name
