Check for newly-broken concurrencies by the addition of a new point along a route

[jteresco]

From @cockroachking at https://forum.travelmapping.net/index.php?topic=7758.msg43186#msg43186

One thing I'll add for the concurrency checker that would improve its usefulness is checking to see if points are added on one route, but not the other. For example, a point request comes in for Route A, and only Route A gets the new point, while concurrent with Route B. This is something that I don't believe is flagged currently, but probably results in about half of the broken concurrencies that come up.