remove bitrot, update and set versions of all deps, notably gfx & nalgebra

src/lib.rs

@@ -1,9 +1,8 @@
-#![feature(conservative_impl_trait)]
+#![feature(iterator_flatten)]
 
 #[macro_use] extern crate gfx;
-#[macro_use] extern crate log;
+#[allow(unused_imports)] #[macro_use] extern crate log;
 extern crate nalgebra as na;
-extern crate num_traits;
 extern crate piston;
 
 pub mod arena;