All of the old styles had visibility issues, and rendering code was a bit too overcomplicated. This fixes all if it by rendering chapters as diamond indicators on top of the timeline.
`timeline_chapters` option is now a boolean, and `timeline_chapters_opacity` & `timeline_chapters_width` have been removed.
This means chapter rendering is no longer configurable, as they resize based on timeline size, and inherit its opacity and border size, so I don't see what anyone would want to configure here, but I'm sure I'll get some requests as always :'(.
ref #206
3c85721f1a