Merging two timelines

[monteiz]

I was not able to find a way to merge two timelines (if there is a built-in way, please tell me).

I thought then it may be nice to have an addTimeline method to the timeline class instance.

It's signature would be:

addTimeline(timeline, offset = 0)

[Optional] Do you want to help provide this feature?

I can create such a method.