Merge pull request #3576 from haukepetersen/mv_netopt

cpu/nrf51/radio/nrfmin/nrfmin.c

drivers/include/kw2xrf.h

drivers/kw2xrf/kw2xrf.c

drivers/ng_at86rf2xx/ng_at86rf2xx_netdev.c

drivers/xbee/xbee.c

sys/include/net/netopt.h

sys/include/net/ng_netapi.h

sys/include/net/ng_netbase.h

sys/include/net/ng_netdev.h

sys/include/net/ng_nettest.h

sys/net/application_layer/ng_zep/ng_zep.c

sys/net/crosslayer/ng_netapi/ng_netapi.c

sys/net/crosslayer/ng_nettest/ng_nettest.c

sys/net/link_layer/ng_netdev_eth/ng_netdev_eth.c

sys/net/network_layer/ng_ipv6/netif/ng_ipv6_netif.c

sys/net/network_layer/ng_ndp/ng_ndp.c

sys/net/network_layer/ng_sixlowpan/iphc/ng_sixlowpan_iphc.c

sys/shell/commands/sc_netif.c