Use more memory for samtools sort
Use more memory for samtools sort

This reduces the number of temporary files that are created. The default is
768 MB, now it is 4 GB. Files on disk were just ca. 180 MB, which means that
hundreds of files are created for a final BAM that has perhaps 50 GB.

An even nicer solution would be to use as much memory as is available minus
about 8 GB for BWA-MEM.

marcelm/CAW,marcelm/CAW,marcelm/CAW,szilvajuhos/CAW,szilvajuhos/CAW,szilvajuhos/CAW