Implementing superset attributes. Custom not handled right now,
but flatgs are set as to wether to include them. Need to be passed
into the custom query
implemented the custom super set attrs.
does so by adding to the query function
3 params for the 3 domains. Form which
we can include the custom attr or not.
Effectively adds all custom attrs to the
attr list
Added test case for super set attribute all_attrs
And made the test cases a little more modular
TODO: add test cases for other super set attrs
      add test cases for BAD syntax etc....
Fixed querying of custom metadata superset attributes.
There was a bug where if you did not specify any system
attrs, it would never be in the list passed to the custome
query function, and thus never getting ot query custom metadata.
Fix: Added the uri to the specific attr list so that it would be
included. the uri is then not included in the final list of dicts,
since it is not in the original attr list/
We then use a list comprehension to delete any empty dicts.
finished the test cases for superset attrs
WILL DO: 'bad' test cases. give it wrong answers and test the error codes
Added test cases for when there is no attributes param
in the request.

Fixed the behaviour of when there is no attributes param to
fir the API spec
 Added test case for bad attrs
Fixed pep8 errors in test_server.py