Fixes some warnings in numeric_encoded tests

lib/src/store/numeric_encoder.rs

@@ -702,10 +702,6 @@ impl<S: StringStore + Default> Default for Encoder<S> {
     }
 }
 
-mod test {
-    use model::*;
-    use store::numeric_encoder::*;
-
 #[test]
 fn test_encoding() {
     let encoder: Encoder<MemoryStringStore> = Encoder::default();
@@ -733,5 +729,3 @@ mod test {
 
     assert_eq!(size_of::<EncodedTerm>(), 24);
 }
-
-}