https://github.com/apmon/openstreetmap-website/compare/routing2
https://github.com/apmon/openstreetmap-website/blob/9755c3ae0a8d0684d43760f91dc864ff42d8477a/app/views/routing/start.js.erb
- *** draggable start/end markers
*** translation (including all alerts and presentation)
*** export GPX
*** URL history (or do we consciously not want to support that?)
*** spinner when waiting for result (beneath 'Go' button?)
*** add YOURS engine
- *** add GraphHopper engine
*/
var TURN_INSTRUCTIONS=["",