- previously built the entire adjacency table (full communication!)
  but this is only strictly needed when using 'scheduled' as the
  default communication mode. For blocking/nonBlocking modes this
  information is not necessary at that point.

  The processorTopology::New now generally creates a smaller amount of
  data at startup: the processor->patch mapping and the patchSchedule.

  If the default communication mode is 'scheduled', the behaviour is
  almost identical to previously.

- Use Map<label> for the processor->patch mapping for a smaller memory
  footprint on large (ie, sparsely connected) cases. It also
  simplifies coding and allows recovery of the list of procNeighbours
  on demand.

- Setup the processor initEvaluate/evaluate states with fewer loops
  over the patches.

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BREAKING: procNeighbours() method changed definition

- this was previously the entire adjacency table, but is now only the
  processor-local nei...