added screed and read_parser streaming testing

Marked as known failing since they currently fail.
Will investigate.

Relevant to #393, #654
These are the actual streaming tests themselves, the larger functions are just slightly abstracted helper functions. Michael wanted me to test each permutation of the files (i.e. uncompressed fasta, gzip'd fasta, uncompressed fastq, gzip'd fastq, etc.), hence individual functions.