+ adjust gather_reads (don't use itertool.chain)
+ adjust gather_reads (don't use itertool.chain)

  - for some reason on certain bam files, pysam's fetch isn't reading
    both combined iterators, but just one.  So we're only getting the
    reads for one side of the breakpoint.

    I'm adjusting the logic to go through one iterator/pysam-fetch at a
    time, to resolve this situation.

hall-lab/svtyper,hall-lab/svtyper,hall-lab/svtyper