id property Null safety

1. now8
2. domain
3. Stop
4. id property

Stop class

1. Constructors
2. Stop
3. fromJson
4. Properties
5. code
6. hashCode
7. id
8. latitude
9. longitude
10. name
11. routeWays
12. runtimeType
13. zone
14. Methods
15. noSuchMethod
16. toString
17. Operators
18. operator ==