Import std::num::NumCast explicitly.

It was removed from the prelude as part of <rust-lang/rust#18827>.

Author: Ms2ger

src/length.rs

@@ -10,7 +10,7 @@
 
 use scale_factor::ScaleFactor;
 
-use std::num::{cast, Zero};
+use std::num::{NumCast, cast, Zero};
 
 /// A one-dimensional distance, with value represented by `T` and unit of measurement `Unit`.
 ///

src/point.rs

@@ -11,7 +11,7 @@ use length::Length;
 use size::Size2D;
 
 use std::fmt;
-use std::num::Zero;
+use std::num::{NumCast, Zero};
 
 #[deriving(Clone, Decodable, Encodable, Eq, Hash, PartialEq)]
 pub struct Point2D<T> {

src/rect.rs

@@ -13,7 +13,7 @@ use point::Point2D;
 use size::Size2D;
 use std::cmp::{PartialEq, PartialOrd};
 use std::fmt;
-use std::num::Zero;
+use std::num::{NumCast, Zero};
 
 #[deriving(Clone, Decodable, Encodable, PartialEq)]
 pub struct Rect<T> {

src/scale_factor.rs

@@ -8,7 +8,7 @@
 // except according to those terms.
 //! A type-checked scaling factor between units.
 
-use std::num::{cast, One};
+use std::num::{NumCast, cast, One};
 
 /// A scaling factor between two different units of measurement.
 ///

src/side_offsets.rs

@@ -10,7 +10,7 @@
 //! A group of side offsets, which correspond to top/left/bottom/right for borders, padding,
 //! and margins in CSS.
 
-use std::num::Zero;
+use std::num::{NumCast, Zero};
 
 /// A group of side offsets, which correspond to top/left/bottom/right for borders, padding,
 /// and margins in CSS.

src/size.rs

@@ -11,7 +11,7 @@ use length::Length;
 
 use std::cmp::PartialEq;
 use std::fmt;
-use std::num::Zero;
+use std::num::{NumCast, Zero};
 
 #[deriving(Clone, Decodable, Encodable, PartialEq)]
 pub struct Size2D<T> {