Update flows report to include total flows and unique flows

[fklassen]

As per @abiryukov suggestion

[fklassen]

Examples of final reports.

# tcpreplay -i eth7 -tK --loop 50 --unique-ip --flow-expiry 30 --netmap smallFlows.pcap 
Switching network driver for eth7 to netmap bypass mode... done!
File Cache is enabled
Actual: 713050 packets (460826550 bytes) sent in 0.385415 seconds.
Rated: 1195663246.1 Bps, 9565.30 Mbps, 1850083.67 pps
Flows: 69550 flows, 60450 unique, 9100 expired, 180454.83 fps, 712150 flow packets, 900 non-flow
Statistics for network device: eth7
    Attempted packets:         713050
    Successful packets:        713050
    Failed packets:            0
    Truncated packets:         0
    Retried packets (ENOBUFS): 0
    Retried packets (EAGAIN):  0
Switching network driver for eth7 to normal mode... done!

# tcpreplay -i eth7 -tK --loop 50 --unique-ip --flow-expiry 30 --netmap bigFlows.pcap 
Switching network driver for eth7 to netmap bypass mode... done!
File Cache is enabled
Actual: 39580750 packets (17770889200 bytes) sent in 15.00 seconds.
Rated: 1181697178.0 Bps, 9453.57 Mbps, 2631970.75 pps
Flows: 2925250 flows, 2034300 unique, 890950 expired, 194518.10 fps, 39558950 flow packets, 21800 non-flow
Statistics for network device: eth7
    Attempted packets:         39580750
    Successful packets:        39580750
    Failed packets:            0
    Truncated packets:         0
    Retried packets (ENOBUFS): 0
    Retried packets (EAGAIN):  0
Switching network driver for eth7 to normal mode... done!