Made yml version more accomodating according to the given version
Added validation for docker-compose before we pull the image.
Command: docker-compose -f docker-compose.yml config
If it fails logs will contain POD_BAD_MANIFEST_FAILURE and POD Status will be updated as POD_COMPOSE_CHECK_FAILED
A log has been added to show the time lapsed since app launch till after image pull.
Log: "Time elapsed since App launch: 10s"
Rearranged code to retry logging logs after mesos status has been sent.