Initial support for queuing multiple zones

[stephenwoodford]

Relates to #3

Still needs some work and testing, but I was able to get initial support for MultiZone started.

Things that work:

• Clicking multiple zones within a second starts a queue with those zones.
• Using Siri to ask for multiple zones in a HomeKit "room" to be run like backyard now works.

Things that I've found that don't work quite yet:

• When you click to stop the Quick Run Queue, only one of the zones will be updated by a webhook and updated in the Home app, the rest still say Running.

[kcharwood]

This is interesting.

What should be the expected behavior if one zone is running, and you ask for another zone? Does that queue? Also, what does the UI look like for in the home app for a zone that is waiting to run?