Compatibility of Prefix struct for 6LN, 6LR and 6LBR
more distinction between 6LBR and 6LR
abro implementation
non-router
ABRO ref 6CO
cid optimization in adding context in 6LBR
cid optimization in adding context in 6LBR
Merge branch 'refs/heads/dev' into dev-abro

Conflicts:
	examples/6lowpan-nd/6lbr/ex-6lowpannd-6lbr.c
remove auto-conf aaaa::/64 prefix in startup
fixed bug cid
exemple
fixed bug cid
abro
Context prefix timer
new model simu
Merge branch 'refs/heads/dev-abro' into dev

Conflicts:
	core/net/ipv6/uip-ds6.h
	examples/6lowpan-nd/6lbr/ex-6lowpannd-6lbr.c
timeout improvement

Use percentage (def: 10%) and threshold
abro
lifetime context prefix c=0
NCE Garbage-collectible state