Added submit on enter on EditRoutePage
Use current location toggle added to EditRoutePage

Current location toggle initializes based on whether it can get a
current location using the location API.

Also added submit when hitting enter in destination field
Default to use current location

Switched around the logic a little, default to use current location now.
The current location toggle will be switched off and disabled if we
can't get the user's location. Also initializing the form based on the
model so we can navigate to this edit screen from the MainView
Passing max_age parameter to filter to 24 hours
Keeping track of added markers

Removing markers before adding additional markers. Also remove event
listeners on markers.