Cleanup XML parser code

[WJSchakel]

Parts of the XML parser code are quite old and not up to date with changes in OTS and improved coding standards.

[WJSchakel]

• Removed Point2dList, List<Point2d> can be parsed directly
• Removed StripeType, Stripe.Type from road is sufficient
• Removed PerLengthType from XML and bindings, LinearDensity is used instead
• Removed unused methods in Transformer and elsewhere
• Replaced many if-throw with Throw.when()