The alpha constant is for the local optimality T-Test threshold.
Before we used epsilon for the T-Test threshold, but the epsilon
constant is meant to be used for the stretch test(s) only.
This changeset fixes the local optimality T-Test and uses the
epsilon constant for the two stretch tests:
- We test the stretch for the total route against epsilon and
- We test the detour against the epsilon now, too
We can discuss if the second stretch test should actually use
epsilon, too, or a adapted value of it - but definitly not alpha.
- moves collapse into a dedicated set of functions / files
- make collapse scenarios distinct (slight performance cost)
- reduce verbosity for short name segments (now actually working, was supposed to do so before)
