Auto merge of #399 - servo:frewsxcv-revert, r=SimonSapin

Revert "Derive `Copy` for some structures."

This reverts commit efffb61.

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/rust-url/399)
<!-- Reviewable:end -->

Author: bors-servo

idna/src/uts46.rs

@@ -23,7 +23,7 @@ include!("uts46_mapping_table.rs");
 pub static PUNYCODE_PREFIX: &'static str = "xn--";
 
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Debug)]
 struct StringTableSlice {
     // Store these as separate fields so the structure will have an
     // alignment of 1 and thus pack better into the Mapping enum, below.
@@ -41,7 +41,7 @@ fn decode_slice(slice: &StringTableSlice) -> &'static str {
 }
 
 #[repr(u8)]
-#[derive(Clone, Copy, Debug)]
+#[derive(Debug)]
 enum Mapping {
     Valid,
     Ignored,
@@ -52,7 +52,6 @@ enum Mapping {
     DisallowedStd3Mapped(StringTableSlice),
 }
 
-#[derive(Clone, Copy)]
 struct Range {
     from: char,
     to: char,