Things to do for RPL, in random order of priority
- Pad1 and PadN, check all the messages
- Re-consider DAO generation. In particular see section 9.8.
  * DAOs could be not "forwarded". They could be re-created from the RT.
  * A node *can* issue NO-Path DAOs if the RT expires.
  * NO-Path DAO should be sent to parents not anymore DAOparent (when purging parents).
- Add test, examples and doumentation
- Implement multicast DAOs
- Implement multicast routes support

Things to do for 6LoWPAN, in random order of priority
Global Addresses are not built correctly 
  RFC 4944 , section 6.  Stateless Address Autoconfiguration tells that global addresses should be
  [64 bits]:yyyy:00ff:fe00:xxxx
  where yyyy is the PAN id and xxxx is the short address.
Link local addresses are correct.

Tests to be performed:

General issues to ns-3 or whatever.
- The routing can be set only on an IP-layer basis
  A node can only have *one* IPv6 layer, hence the routing is the very same for all the NetDevices.
  This is a problem for multi-protocol nodes, e.g., border routers.
  The solution is to embed the interface handling *inside* the routing protocol. E.g., BindToNetDevice.
