Update INSTALL
Update INSTALL

AFAIK some info here was previously wrong.
TyberiusPrime/pysam,pysam-developers/pysam,kyleabeauchamp/pysam,kyleabeauchamp/pysam,kyleabeauchamp/pysam,bioinformed/pysam,TyberiusPrime/pysam,bioinformed/pysam,bioinformed/pysam,pysam-developers/pysam,TyberiusPrime/pysam,kyleabeauchamp/pysam,TyberiusPrime/pysam,bioinformed/pysam,pysam-developers/pysam,pysam-developers/pysam,kyleabeauchamp/pysam,TyberiusPrime/pysam,bioinformed/pysam