use switch-case statement
merge indicateRoutingFailure() into updateRouteState()
stop progress animation only after the last route request has finished
hide result label when state changes to Downloading rather than every time the progress animation updates

* avoids race condition between progress timer and route retrieval (where label is set to visible)
only switch to Retrieved state when last route request hast finished
rename and make static
[API change] AlternativeRoutesModel
avoid duplicate route points
deactivate some plugins
[API change] port to routing API