Icon order

```
Hi

I'm starting the use of this tool.

I have a problem.

Te route have 8 points to solve the reoute.

The problem is that the point A allwais must before Point B and point C allways
muest before point D.

I try to use to a car transport and in point A y take the car and the point B
is the destinatios.

Do you have any solution to specify in the location list the requiered location.

Thanks

Correo@microdataes.com
```

Original issue reported on code.google.com by `miguelca...@gmail.com` on 20 Apr 2011 at 4:45

The issue names no files, tests, or entry points. Start by clarifying how location order constraints should be specified and reviewing the repository's routing and location-selection entry points. Done should mean the tool supports requiring one named point to precede another in the generated route.

Written by the indexing model from the issue text.