Partially remove Seek constraint from ListingStream, extract fifo node in tests

src/listing_stream.rs

@@ -7,7 +7,7 @@ use {
 };
 
 #[derive(Debug)]
-pub struct ListingStream<R: Read + Send + Seek> {
+pub struct ListingStream<R: Read + Send> {
     pub length: u32,
     reader: R,
 }

src/node.rs

@@ -519,5 +519,6 @@ mod tests {
             eprintln!("Read incorrect filetype: {:?}", node.filetype);
             panic!();
         };
+        node.extract(Some("test/output")).unwrap();
     }
 }