Remove dependency on the rand crate

Cargo.toml

@@ -18,7 +18,6 @@ path       = "src/sdl2/lib.rs"
 [dependencies]
 bitflags = "^1"
 libc = "^0.2"
-rand = "^0.6"
 lazy_static = "^1"
 
 [dependencies.num]
@@ -33,6 +32,9 @@ version = "^0.32"
 version = ">= 1.0, <= 1.3"
 optional = true
 
+[dev-dependencies]
+rand = "^0.7"
+
 [features]
 
 unsafe_textures = []

src/sdl2/pixels.rs

@@ -1,7 +1,3 @@
-extern crate rand;
-use self::rand::Rng;
-use self::rand::distributions::{Distribution, Standard};
-
 use num::FromPrimitive;
 use std::mem::transmute;
 use std::convert::TryFrom;
@@ -171,16 +167,6 @@ impl From<(u8, u8, u8, u8)> for Color {
     }
 }
 
-impl Distribution<Color> for Standard {
-    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Color {
-        if rng.gen() {
-            Color::RGBA(rng.gen(), rng.gen(), rng.gen(), rng.gen())
-        } else {
-            Color::RGB(rng.gen(), rng.gen(), rng.gen())
-        }
-    }
-}
-
 pub struct PixelMasks {
     /// Bits per pixel; usually 15, 16, or 32
     pub bpp: u8,