Delete empty lines in help/usage
Respect alphabetic order (flowgrind -h)
Typo in help
Put 'same as' in parenthesis (flowgrind -h)
Fix description of option -Z
* Specifiy in each option which unit (byte, second, ...) we use
* Unified unit for time to 's'. Not use 'second' or 'sec' anymore
Highlight that -T and -Z cannot combined
Clarifies that bock size means message size. Needed because every
other tool (netperf, iperf, sockperf) uses this term
Since commit 2d953cda7b8e54a00423b9b626be1bb410861bd2 the random seed is
a flow option and not a general option anymore. Author forgot to change
the optparser