In case of ties in the "r -LB" , RN choice should only be between the LB neighbors, not all neighbors

[lucasmation]

As discussion in issue #36 indicates, the -r LB (longest border) criteria will handle ties by assining the problematic area to a RN (random neighbor). However this random choice occurs among all neighbors, including the ones that have the smaller borders.

In case of ties in "r -LB" criteria, -RN should choose only among the neighbors that have the longest border.

(and please make sure this change trickes down to pprepair-new, or any version that runs on linux)