Some small changes to get Servo compiling

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "euclid"
-version = "0.8.0"
+version = "0.8.1"
 authors = ["The Servo Project Developers"]
 description = "Geometry primitives"
 documentation = "http://doc.servo.org/euclid/"

src/length.rs

@@ -20,7 +20,7 @@ use std::ops::{AddAssign, SubAssign};
 use std::marker::PhantomData;
 use std::fmt;
 
-#[derive(RustcDecodable, RustcEncodable)]
+#[derive(Clone, Copy, RustcDecodable, RustcEncodable)]
 pub struct UnknownUnit;
 
 /// A one-dimensional distance, with value represented by `T` and unit of measurement `Unit`.
@@ -36,7 +36,7 @@ pub struct UnknownUnit;
 /// another. See the `ScaleFactor` docs for an example.
 // Uncomment the derive, and remove the macro call, once heapsize gets
 // PhantomData<T> support.
-#[derive(RustcDecodable, RustcEncodable)]
+#[derive(Clone, Copy, RustcDecodable, RustcEncodable)]
 pub struct Length<T, Unit>(pub T, PhantomData<Unit>);
 
 impl<Unit, T: HeapSizeOf> HeapSizeOf for Length<T, Unit> {
@@ -64,8 +64,6 @@ impl<T, Unit> Length<T, Unit> {
     }
 }
 
-impl<T: Copy, Unit> Copy for Length<T, Unit> {}
-
 impl<Unit, T: Clone> Length<T, Unit> {
     pub fn get(&self) -> T {
         self.0.clone()
@@ -157,15 +155,6 @@ impl<Unit, T0: NumCast + Clone> Length<T0, Unit> {
     }
 }
 
-// FIXME: Switch to `derive(Clone, PartialEq, PartialOrd, Zero)` after this Rust issue is fixed:
-// https://github.com/mozilla/rust/issues/7671
-
-impl<Unit, T: Clone> Clone for Length<T, Unit> {
-    fn clone(&self) -> Length<T, Unit> {
-        Length::new(self.get())
-    }
-}
-
 impl<Unit, T: Clone + PartialEq> PartialEq for Length<T, Unit> {
     fn eq(&self, other: &Length<T, Unit>) -> bool { self.get().eq(&other.get()) }
 }

src/matrix2d.rs

@@ -16,6 +16,7 @@ use std::ops::{Add, Mul, Sub};
 use std::marker::PhantomData;
 
 define_matrix! {
+    #[derive(Clone, Copy, Eq, Hash, PartialEq)]
     pub struct TypedMatrix2D<T, Src, Dst> {
         pub m11: T, pub m12: T,
         pub m21: T, pub m22: T,

src/side_offsets.rs

@@ -21,7 +21,7 @@ use heapsize::HeapSizeOf;
 /// A group of side offsets, which correspond to top/left/bottom/right for borders, padding,
 /// and margins in CSS.
 define_vector! {
-    #[derive(Debug)]
+    #[derive(Clone, Debug)]
     pub struct TypedSideOffsets2D<T, U> {
         pub top: T,
         pub right: T,