Add a new DumpFormat mode for sniff file statistics (without parsing):

CSV format:
- sniff file name
- time of first packet
- time of last packet
- sniff duration (seconds)
- packet count
- total packets size (bytes)
- average packet size (bytes)
- smaller packet size (bytes)
- larger packet size (bytes)

(written to console and log file)
(this was done some time ago, not really useful)