added screed and read_parser streaming testing

Marked as known failing since they currently fail.
Will investigate.

Relevant to #393, #654
Actually, this appears to break in screed 0.7.1. Not totally sure why; I feel like @mr-c and I had a (verbal) discussion about this. (He was the one who told me to make this change as I recall but I do not remember why nor do I have a documented reason. I'll mention this in a relevant screed thread after verifying that it is screed 0.7.1 causing it.)