metadata: structs now derive Copy & Clone

src/metadata/cuex.rs

@@ -63,7 +63,7 @@ impl fmt::Display for NrgCuex {
 }
 
 
-#[derive(Debug)]
+#[derive(Copy, Clone, Debug)]
 pub struct NrgCuexTrack {
     pub mode: u8,
     pub track_number: u8,

src/metadata/mtyp.rs

@@ -29,7 +29,7 @@ use ::error::NrgError;
 use super::readers::read_u32;
 
 
-#[derive(Debug)]
+#[derive(Copy, Clone, Debug)]
 pub struct NrgMtyp {
     pub size: u32,
     pub unknown: u32,

src/metadata/sinf.rs

@@ -29,7 +29,7 @@ use ::error::NrgError;
 use super::readers::read_u32;
 
 
-#[derive(Debug)]
+#[derive(Copy, Clone, Debug)]
 pub struct NrgSinf {
     pub size: u32,
     pub nb_tracks: u32,