Default to stdout for traceroute's JSON output

[insomniacslk]

Now the JSON output is by default on stdout, and any other output goes to stderr, making it easier to feed the JSON data to other programs, e.g. jq .

Fixes #80

Signed-off-by: Andrea Barberio insomniac@slackware.it

[insomniacslk]

CC @omribahumi