Many improvements

Now that the watch face is (very) stable, I have added many new
features:
Vibrations on Dis/Connection
New Notification System (using the MUSIC_LAYER)
Smart buttons:
## When iPhone is connected
* UP — Siri
* UP-Hold — Find My iPhone
* Middle — Display current conditions and update
* Down — Next Music
* Down-Hold — Play/Pause Music

## When iPhone is connected
* UP — Nothing
* UP-Hold — Reminds you you’re disconnected, but still try to “Find
iPhone”… just in case
* Middle — Display current conditions
* Down — Turn off the light
* Down-Hold — Turn on the light for 2 minutes