Do not precalculate the distance to the nearest transit stop.

These searches were unbounded in time/distance (as they must be to be generally correct)
which makes graph building ultraslow on large graphs.

Also:
Rename function to "shouldSearchTerminate" so it matches description in Javadoc
Add traverseVisitor calls to GenericDijkstra
Remove misleading tests.

In TestRequest, three tests were failing after the last commit:
testFirstTrip, testTransferPenalty2, testPreferredTripToTripTransfer

However they continued failing even when I disabled all new or modified code.
On a hunch I set the heuristic value to zero, and they continued failing.
Apparently the search results were dependent on mistakes in the original
DefaultRemainingWeightHeuristic, which was clearly incorrect but apparently
also not admissible.

The removed tests are checking very specific characteristics of results on
a real-world network, and those results can easily change.
remove unused classes