fixes from review

types/part_set.go

@@ -231,12 +231,6 @@ func (ps *PartSet) GetReader() io.Reader {
 		PanicSanity("Cannot GetReader() on incomplete PartSet")
 	}
 	return NewPartSetReader(ps.parts)
-
-	buf := []byte{}
-	for _, part := range ps.parts {
-		buf = append(buf, part.Bytes...)
-	}
-	return bytes.NewReader(buf)
 }
 
 type PartSetReader struct {

types/tx.go

@@ -15,7 +15,7 @@ func (txs Txs) Hash() []byte {
 	case 0:
 		return nil
 	case 1:
-		return txs[0]
+		return merkle.SimpleHashFromBinary(txs[0])
 	default:
 		left := Txs(txs[:(len(txs)+1)/2]).Hash()
 		right := Txs(txs[(len(txs)+1)/2:]).Hash()