Update sendspin-cpp and add static delay support

[genehand]

I updated to the latest sendspin-cpp library, only to discover that my soundbar needs a delay adjustment. This also adds initial_static_delay to the config for that as well.

Thanks for giving an old Pi some new tricks!

[bethesque]

Thanks, I'm just porting from snapcast, and need the delay too.

[bethesque]

I've pulled your changes into my own fork, and I can set the delay successfully, thank you @genehand. You don't happen to be using Music Assistant as your server do you?

[genehand]

Nice, glad it helped. Yeah I am using Music Assistant, working pretty well here although occasionally something gets out of sync. Haven't tracked it down yet, pausing and starting up again sorts it back out.

[LeoLTM]

Thanks for the changes!