consolidate imports

src/view.rs

@@ -1,15 +1,12 @@
-use vr;
-use vr::{AsMatrix4, VR};
+use vr::{self, AsMatrix4, VR};
 
 extern crate gfx_device_gl;
-extern crate nalgebra as na;
-extern crate num_traits;
 extern crate piston_window;
 
 use gfx;
 use gfx::Device;
 use gfx::traits::FactoryExt;
-use self::na::{Inverse, ToHomogeneous};
+use na::{self, Inverse, ToHomogeneous};
 use self::piston_window::{PistonWindow, Window};
 
 pub type ColorFormat = gfx::format::Srgba8;