Bug Fix: Fix output volume from seeking

Fixes output volume setting on seek or audio output restart on format
change. Also safeguards these setters so they don't go off if the nodes
aren't actually allocated.

Signed-off-by: Christopher Snowhill <kode54@gmail.com>

Audio/Chain/BufferChain.m

@@ -365,8 +365,15 @@
 
 - (void)setVolume:(double)v {
 	AudioPlayer * audioPlayer = controller;
-	OutputNode *outputNode = [audioPlayer output];
-	[outputNode setVolume:v];
+	if(audioPlayer) {
+		OutputNode *outputNode = [audioPlayer output];
+		if(outputNode) {
+			[outputNode setVolume:v];
+		}
+	}
+	if(inputNode) {
+		[inputNode setLastVolume:v];
+	}
 }
 
 @end