WPS process to rank points along a track/route

Update of ktcorby's efforts on PR#73
Break apart for readability?

```scala
val (nTubeCells, gridSize) = 
  rankingValues.headOption match {
    case Some((_, rv)) => (rv.nTubeCells, rv.gridDivisions)
    case None      => (0, 0)
  }
```