add Distances
Adds a list of distanceData to the model.
Return
a map containing the pairs of locations created by the names of the distances in the list
Assumes that matrix is square and contains the from-to distances. Any values on the diagonal are ignored. No values can be 0.0
Return
a map containing the pairs of locations created. Each location is named Loc_k, where k is the index of the location in the array