[Bug] marker detection reliability issues

[Novakasa]

there is a potential issue with detecting markers reliably, potentially due to the changes introduced in af6be84 and related commits, to filter out colors that are never used as markers (mainly to make green baseplates and similar possible)

@TekyTeky you reported recently that you have seen marker errors, so this might be that. I have been able to test a bit with my layout on the weekend, and I had a few marker errors that seemingly came in random places. I am planning to add a automatic color data dump after unexpected markers so I can take a look why the wrong marker was detected. This is tracked in #144.

[TekyTeky]

I believe I have not received a recent marker error when manually selecting and moving a train in a forward direction. They usually happen when in random mode, both directions. I thought since delays were introduced at blocks, but that may be coincidental.

[Novakasa]

I implemented #144 now (on Master). Each time you get a marker error, 2 new files will be generated in the log directory. One .txt file that contains the color data, and a plot (.png file) that visualizes the data. This should help in cases where some markers are false detections. This will help a lot to try to debug any issues, so @TekyTeky next time you get a marker error, please post these 2 files along with the regular logs here.

Example for how the plot might look like:

It is weird that you only seem to get marker errors in "random mode", my guess is that this just might be due to statistics? When I run random mode with multiple trains, trains will just run a lot more, and with multiple trains at the same time. But if the issues are not a sensor processing issue, then this could definitely be the case.