ToDo:
 * ability to specify on a per-op base the min version, otherwise a n/a occurs
 * --skip_group=1,2,3 --skip_op=4,3,2,6  to skip groups or ops
 * --group=1,2,3 --op=1,2,34             to only run these ops or groups
 * when a group is n/a for first version, and relative summary requested:
   search for first not n/a version and set this to $base instead of having
   all n/a
 * append a total average to summary

Tels <http://bloodgate.com/perl/>