ss: add option to print socket information on one line

ss: add option to print socket information on one line

Multi-line output in ss makes it difficult to search for things with
grep. This new option will make it easier to find sockets matching
certain criteria with simple grep commands.

Example without option:
$ ss -emoitn
State      Recv-Q Send-Q Local Address:Port               Peer Address:Port
ESTAB      0      0      127.0.0.1:13265              127.0.0.1:36743               uid:1974 ino:48271 sk:1 <->
	 skmem:(r0,rb2227595,t0,tb2626560,f0,w0,o0,bl0,d0) ts sack reno wscale:7,7 rto:211 rtt:10.245/16.616 ato:40 mss:65483 cwnd:10 bytes_acked:41865496 bytes_received:21580440 segs_out:242496 segs_in:351446 data_segs_out:242495 data_segs_in:242495 send 511.3Mbps lastsnd:2383 lastrcv:2383 lastack:2342 pacing_rate 1022.6Mbps rcv_rtt:92427.6 rcv_space:43725 minrtt:0.007

Example with new option:
$ ss -emoitnO
State    Recv-Q Send-Q          Local Address:Port            Peer Address:Port
ESTAB    0      0                   127.0.0.1:13265              127.0.0.1:36743 uid:1974 ino:48271 sk:1 <-> skmem:(r0,rb2227595,t0,tb2626560,f0,w0,o0,bl0,d0) ts sack reno wscale:7,7 rto:211 rtt:10.067/16.429 ato:40 mss:65483 pmtu:65535 rcvmss:536 advmss:65483 cwnd:10 bytes_sent:41868244 bytes_acked:41868244 bytes_received:21581866 segs_out:242512 segs_in:351469 data_segs_out:242511 data_segs_in:242511 send 520.4Mbps lastsnd:14355 lastrcv:14355 lastack:14314 pacing_rate 1040.7Mbps delivery_rate 74837.7Mbps delivered:242512 app_limited busy:1861946ms rcv_rtt:92427.6 rcv_space:43725 rcv_ssthresh:43690 minrtt:0.007

Signed-off-by: Josh Hunt <johunt@akamai.com>
Signed-off-by: David Ahern <dsahern@gmail.com>