Add HSL geocoder.

HSL journey planner API requires coordinates, i.e. geocoding must be
done separately, i.e. we need we need a separate geocoder (we could use
Nominatim too, but maybe HSL's geocoder is better and at least provides
names people are used to when using reittiopas.fi).

http://developer.reittiopas.fi/pages/en/home.php
Add 'params' argument to routing functions.
Reduce quotation marks.
Add methods to deal with configuration options of type set.

Actually implemented as lists, but containing unique values.
Add params to routing page.
Indent current position item.
Add HSL Journey Planner.