Greatly optimize isochrone ring generation.

Remove the h/v sets and use a processQ.
Optimize isochrone sampling with a SparseMatrix.

This divide by 3/4 the sampling time.
Remove XYindex with it's slow translated() method.
Remove all Maps from the implementation.
Add fastDistance/Length with cached cos(lat).
Optimize isochrone by caching cos(lat).

Correct distance computation (d is not homogeneous coordinates).
Isochrone: simplify sample closing to 1 stage.
Isochrone: provide defaults for neighbors if avail.
Isochrone: various refactoring and renaming.

- Add routerId parameter to the request.
- Add algorithm parameter to select between implementations.
- Rename various classes.
- Extract IsochroneSPTRenderer interface.
- Rename web-service from /iso2 to /isochrone.
Isochrone: remove too small rings.