Removes input when it's finished.

Removes an input from the array of inputs when it's 'finished'.

lib/mixer.js

@@ -88,6 +88,10 @@ Mixer.prototype.input = function (args) {
 	});
 	this.inputs.push(input);
 	
+	input.on('finish', () =>{
+		this.inputs.splice(this.inputs.indexOf(input), 1);
+	});
+
 	return input;
 };