Support the follwoing arguments in the ctr parameter parser:

 - add 'delta_disks', 'data_offset' taking int and sector respectively

 - 'raid10_use_near_sets' bool argument to optionally select
   near sets with supporting raid10 mappings
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>