Porting FASTQ IO

This a step towards porting FASTQ over to skbio.io as addressed in #681

I have a sniffer and reader written up and added some additional formatting checks.
Also, I would like to add an additional doctest to test to for phred-offset=64, 
but I'm not sure how to do it.  
This won't do anything at all. An opened filehandle is provided to every registered reader/sniffer. 
Also, we can't enforce binary vs text mode when opening files, which is a flaw we are aware of, fortunately it looks like binary mode wasn't strictly required anyways.