Add methods for executing a command, interleaving stdout and stderr, and return exit status in addition to command output.
Add methods for executing a command, interleaving stdout and stderr, and return exit status in addition to command output.

nh13/picard,annkupi/picard,nh13/picard,broadinstitute/picard,alecw/picard,broadinstitute/picard,alecw/picard,annkupi/picard,alecw/picard,annkupi/picard,alecw/picard,nh13/picard,annkupi/picard,broadinstitute/picard,broadinstitute/picard,nh13/picard,broadinstitute/picard