Enum extension continued

Updated docstring formatting for insertion into vistrails. Now able to handle doc types that include multiple types (e.g. scalar and tuple). Also able to load functions that have 'output' listed in 'Parameters' instead of in 'Returns' in fact many functions do not include a 'Returns' section since 'output' is listed as a parameter.
This will raise an exception if `len(original_description) == 0`