API to start a certain song at a specific time

[LordSimal]

It would be really cool if there is a API to start playing a certain song at a specific time.

As already mentioned in #20 I have certain "choir requirements" and this would allow me to prepare certain positions ahead of time so users only have to click on e.g. "Start of Song X" and it jumps to exactly that song at time 30:45 (just an example of course)