vlan: moved vlan struct from linkinfo to netdev
factory: fixed newlink to not free netdev on discard

The netdev returned by create is not yet reference incremented,
but a pointer to a discovered new netdev object in the device list.
The increment happens later in ni_objectmodel_netif_factory_result.
linkinfo: changed master to masterdev netdev reference
linkinfo: introduced lowerdev netdev reference
vlan: initial refactoring to use link.lowerdev
macvlan: initial refactoring to use link.lowerdev
infiniband: initial refactoring to use link.lowerdev
schema: renamed infiniband parent to (lower)device
infiniband: changed to use <infiniband:child> node
vlan: added protocol (ieee802-1Q, ieee802-1ad)
iflist: cleaned up lowerdev/master name bind
schema: show master device interface property
Merge pull request #126 from mtomaschewski/lowerdev-refactor

Refactored to use link.lowerdev in vlan,macvlan,infiniband-child