Request events when attempting to navigate timestamps, and there are missing events

[MaddieM4]

Will want to look at how the Go version does it, and try to decide what makes sense for JS. I don't want to bikeshed it too much for an iteration of the protocol that will eventually be replaced, but this feature would be useful now.

[MaddieM4]

The Go implementation only requests timestamps as a response to 02-publish-events, if there are any unfamiliar events in the TS list. Going to do it the same way here - there are almost certainly some infinite loop cases to worry about, and the current Go implementation does not run into them.