Add canceled trips function

[deg0nz]

Add canceled trips function to mark canceled trips in the module with strikethrough or 'canceled'-label.

hafas-client v1.3.0 supports this.

[derhuerst]

The changes should be live at vbb.transport.rest now. It's hard to test wether everything works though, as only very few departures get canceled.

[deg0nz]

Commit 2f80af0 implements this.