Vendor dependencies

Let's see how I like this workflow.

vendor/rand/benches/bench.rs

@@ -0,0 +1,34 @@
+#![feature(test)]
+
+extern crate test;
+extern crate rand;
+
+const RAND_BENCH_N: u64 = 1000;
+
+mod distributions;
+
+use std::mem::size_of;
+use test::{black_box, Bencher};
+use rand::{StdRng, Rng};
+
+#[bench]
+fn rand_f32(b: &mut Bencher) {
+    let mut rng = StdRng::new().unwrap();
+    b.iter(|| {
+        for _ in 0..RAND_BENCH_N {
+            black_box(rng.next_f32());
+        }
+    });
+    b.bytes = size_of::<f32>() as u64 * RAND_BENCH_N;
+}
+
+#[bench]
+fn rand_f64(b: &mut Bencher) {
+    let mut rng = StdRng::new().unwrap();
+    b.iter(|| {
+        for _ in 0..RAND_BENCH_N {
+            black_box(rng.next_f64());
+        }
+    });
+    b.bytes = size_of::<f64>() as u64 * RAND_BENCH_N;
+}