• Added responses.matchers.
• Moved responses.json_params_matcher to responses.matchers.json_param_matcher
• Moved responses.urlencoded_params_matcher to
  responses.matchers.urlencoded_param_matcher
• Added responses.query_params_matcher. This matcher allows you to match
  query strings with a dictionary.
• Added auto_calculate_content_length option to responses.add(). When
  enabled, this option will generate a Content-Length header
  based on the number of bytes in the response body.