yarn log does not output all needed information, and is in a binary format

yarn logs does not output attemptid, nodename, or container-id. Missing these makes it very difficult to look through the logs for failed containers and tie them back to actual tasks and task attempts.

Also the output currently includes several binary characters. This is OK for being machine readable, but difficult for being human readable, or even for using standard tool like grep.

The help message can also be more useful to users