Fixed access to invalid {up} relation in sec. opt.

During secondary optimization the {up} relation no longer acts on
networks of a single zone, but has already been changed to act
globally.

Attribute {max_up_net} had been recalculated during secondary optimization.
This used a no longer valid {up] relation.

Now attribute {max_up_net} has been split into two attributes
{max_routing_net} and { max_secondary_net}. Both are calculated when
{up} is still valid.
Ignore supernet with NAT in route and second. opt.

Supernet is only used for {max_routing_net} and { max_secondary_net},
if it has the same NAT tags as original network.

NAT tag that is defined and applied inside the same zone is ignored in
this check.
Merge branch 'master' of https://github.com/hknutzen/Netspoc
Allow owner in attribute 'watchers'.

Element of attribute 'watchers' of owner A is allowed to reference
some other owner B. In this case all admins and watchers of B are
added to watchers of A.