better sigchld signal handler - from perldoc -f waitpid and any::daemon

Signed-off-by: Roy Storey <roy.storey@plantandfood.co.nz>
save command for each process

Signed-off-by: Roy Storey <roy.storey@plantandfood.co.nz>
option to compress queue to make commands distinct (within queue only), set verbose correctly, some stats on sig int

Signed-off-by: Roy Storey <roy.storey@plantandfood.co.nz>
Merge branch 'compress' into devel