computed only over the actual samples, not over the entire
buffer. Also, the initial link estimate is much more conservative now
(16 transmissions) to favor links that have been probed, and which
therefore are likely to have better ETXs.
* Loop detection and untangling. Now uses in-band loop detection that
works.
* Link quality estimation. Now starts with a conservative /
pessimistic estimate for new links.
* Retransmissions. MAC layer and network layer retransmissions are now
decoupled.
* Loss handling. Deals better with losses now.
* Concurrent applications. Each connection now maintains its own
neighbor table with separated cost to sink estimates for each
connection.
