implemented Feed.find_or_generate_by_url method
built feed parser service class
addressed linting errors
refactored parser services
implemented feed item parser
added method to feed model to generate feed items for that feed
added uri normalization
added renormalization and attribute handling to parsers
Merge pull request #13 from cloudspace/67125290_feed_parser_service

implemented Feed.find_or_generate_by_url method