--deaf and --mute arguments to control an already running instance of Mumble

I thought that it'd be useful to be able to mute and deafen myself from the command line or certain scripts. While looking up how to implement this feature, I found you can use the dbus-send command to mute or deafen yourself, but I wasn't able to get this to work properly and decided to make it a bit simpler by just adding the functionality to the program itself.

To deafen yourself on an existing instance, run "mumble --deaf", to mute, run "mumble --mute". Pretty simple.