Route and stop inputs disappear after changing the date input

[ShayAdler]

Steps to reproduce:

• Set time, line number and operator
• Choose route and stop options
• Change the date (which is something I did pretty often when exploring the UI)
• Fill up the route & stop again :(

[ReallyLiri]

The reason for this is that routeId / stopId etc are dependent on date. But I'll see if I can make the code try to match prev date ids to current date ids.