Refactor: a provider now has its own TimetableQuery.
Typo
Query generates URL.
Simplify provider.
Use correct TimetableQuery in examples.
Create RouteQuery.
Check if query is valid.
Generate url in RouteQuery.
Improve RouteQuery.
Unify query related classes.
Use RouteQuery in provider.
Check if RouteQuery is valid.
Improve exception message.