Remove unused Display impl.

src/world/block/mod.rs

@@ -24,7 +24,6 @@
 // Fire (Update State)
 // CobblestoneWall (Connections)
 
-use std::fmt::{Display, Formatter, Error};
 use collision::{Aabb, Aabb3};
 use cgmath::Point3;
 use types::Direction;
@@ -4105,12 +4104,6 @@ pub enum StoneVariant {
     SmoothAndesite,
 }
 
-impl Display for StoneVariant {
-    fn fmt(&self, f: &mut Formatter) -> Result<(), Error> {
-        write!(f, "{}", self.as_string())
-    }
-}
-
 impl StoneVariant {
     pub fn as_string(&self) -> &'static str {
         match *self {