This function pauses the audio currently playing at a specific speaker client (host or host:instance).
Parameter: host
Type: string
Description: Leaving this a null string will pause the audio for the first
instance HomeSeer finds, otherwise use the hostname of the computer you
are interested in pausing audio on. If
more than one instance of the Speaker application is running on "host"
then you may need to specify the instance as well in the format host:instance.
None.