refactor have-bicycle expression into tripAcceptable
lift "trip acceptable" test out of conditionals
separate "trip acceptable" check from transfer check
return possibly adjusted departure search time, not the min transfer time

... more steps toward making timed transfers work with freq trips
move comment
fix bicycle permissions test
reinstate timed transfer + frequencies test

the process for finding the board edges needed to be changed because
there is now no distinction between freq/non-freq and board/alight edges