This function clears all voice commands that were added with AddVoiceCommand.
Parameter:
host (optional)
Type: string
Description: Leaving this a null string will apply the command to the first
instance HomeSeer finds, otherwise use the hostname of the computer for
this command. 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.