Extract regions of bam into smaller bam's

[necrolyte2]

Request was to be able to supply locations for a genome to be extracted
The issue was that IGV would not load entire bam as it was too large so the concept was to extract the smaller regions into seprate bams and then load them with igv

https://gist.github.com/necrolyte2/1950dbd021e023dd78b30bdc48682ee3

@mmelendrez