added screed and read_parser streaming testing

Marked as known failing since they currently fail.
Will investigate.

Relevant to #393, #654
On Thu, Nov 13, 2014 at 08:15:40AM -0800, bocajnotnef wrote:
> > +    fifo = utils.get_temp_filename('fifo')
> > +    in_dir = os.path.dirname(fifo)
> > +    script = scriptpath('normalize-by-median.py')
> > +    args = ['-C', '1', '-k', '17', '-o', 'outfile', fifo]
> > +
> > +    # make a fifo to simulate streaming
> > +    os.mkfifo(fifo)
> > +
> > +    # FIFOs MUST BE OPENED FOR READING BEFORE THEY ARE WRITTEN TO
> > +    # If this isn't done, they will BLOCK and things will hang.
> > +    # rvalues will hold the return from the threaded function
> > +    thread = threading.Thread(target=utils.runscript,
> > +                              args=(script, args, in_dir))
> > +    thread.start()
> > +
> > +    ifile = io.open(ifilename, 'rb')
> 
> In all of the screed tests there's at least a an 
> 
> ```assert os.path.exists(outfile)```
> 
> or similar. I'm not sure how the exception doesn't horribly break things. WIll investigate.

Well, the output file will exist if there is an input file.   But should
look at the contents, maybe...