Fix clang warnings:

Remove duplicate synthesize for totalBytesRead
Add placeholder dealloc for ASINetworkQueue

@@ -1395,7 +1395,6 @@ static NSError *ASIUnableToCreateRequestError;
 @synthesize mainRequest;
 @synthesize totalBytesRead;
 @synthesize showAccurateProgress;
-@synthesize totalBytesRead;
 @synthesize uploadBufferSize;
 @synthesize defaultResponseEncoding;
 @synthesize responseEncoding;

@@ -40,6 +40,11 @@
 	return self;
 }
 
+- (void)dealloc
+{
+	[super dealloc];
+}
+
 - (void)go
 {
 	if (!showAccurateProgress) {