InstData Import: do not pass flagstat path into helpers run flagstat methods
InstData Import: pass bam path into helpers load flagstat methods
InstData Import: change definition of is_paired_end to make sure there are actual read 1 & 2 in the bam (first 10K reads)
InstData Import: move setting instdata bam metrics to helpers
InstData Import: do not pass in bam path to update metrics
Merge pull request #257 from ebelter/instdata-helpers-flagstat

InstData Import flagstat and metrics modifications.