add option to print unix timestamp in trace tool
add option to print unix timestamp in trace tool

tuxology/bcc,tuxology/bcc,tuxology/bcc,brendangregg/bcc,tuxology/bcc,iovisor/bcc,iovisor/bcc,brendangregg/bcc,iovisor/bcc,iovisor/bcc,tuxology/bcc,brendangregg/bcc,brendangregg/bcc,iovisor/bcc,brendangregg/bcc