Add long-term packet repeating at low rate after initial send & repeat

[drFerg]

After initial packet send and repeat, train will continue to run until a new command is received. However, if the train encounters a dodgy rail connection and disconnects from power, its state is reset and it grinds to a halt.

Need to reintroduce a long-term repeat queue for reminding the train if it forgets.

[cam72cam]

Looking forward to this 👍
Let me know if you need any testers, I have a fairly crapped up test loop available.

[drFerg]

Hey Cam, sorry for the lack of updates on this, been busy with other work. Will hopefully get some time to implement this soon.

[drFerg]

I've had a quick go at implementing the long term repeat queue (currently just for high priority packets - speed). It's currently only in my development branch (3220d0d) as I've not had a chance to properly test it beyond checking it compiles.
If you get a chance and fancy trying it out, let me know how it goes.