Identify composite loops in output

[michielbdejong]

For the algorithm it's probably not a good idea to try to filter out composite loops, because

1. it removes robustness - if the common link is down, then the composite loop is still useful
2. it requires more knowledge sharing, and enables nodes to get a richer map of their surroundings

example:

  1
0   3
  2

left triangle: 0-1-2-0
right triangle: 1-2-3-1
full square: 0-1-3-2-0 (composite of 0-1-2-0 and 1-2-3-1)
common link: 1-2