Use compiletest to check Repacketizer lifetimes

tests/compile-fail/repacketize.rs

@@ -0,0 +1,10 @@
+extern crate opus;
+
+fn main() {
+    let mut rp = opus::Repacketizer::new().unwrap();
+    let mut wip = rp.begin().cat_move(
+        &[1, 2, 3]
+        //~^ ERROR borrowed value does not live long enough
+    ).unwrap();
+    wip.out(&mut []);
+}