changed travis tests to samtools 1.2
changed travis tests to samtools 1.2

carolinux/pysam,kyleabeauchamp/pysam,TyberiusPrime/pysam,pysam-developers/pysam,carolinux/pysam,kyleabeauchamp/pysam,nlhepler/pysam,kyleabeauchamp/pysam,bioinformed/pysam,pysam-developers/pysam,TyberiusPrime/pysam,daler/pysam,kyleabeauchamp/pysam,carolinux/pysam,mattions/pysam,nlhepler/pysam,pysam-developers/pysam,mattions/pysam,dannon/pysam,daler/pysam,brendanofallon/pysam,nlhepler/pysam,bioinformed/pysam,dannon/pysam,bioinformed/pysam,pysam-developers/pysam,mattions/pysam,bioinformed/pysam,brendanofallon/pysam,carolinux/pysam,daler/pysam,brendanofallon/pysam,nlhepler/pysam,dannon/pysam,dannon/pysam,TyberiusPrime/pysam,carolinux/pysam,dannon/pysam,mattions/pysam,bioinformed/pysam,TyberiusPrime/pysam,nlhepler/pysam,daler/pysam,brendanofallon/pysam,TyberiusPrime/pysam,brendanofallon/pysam,daler/pysam,mattions/pysam,kyleabeauchamp/pysam