Remove some unused imports

src/libarena/lib.rs

@@ -35,7 +35,6 @@ use std::num;
 use std::ptr;
 use std::mem;
 use std::rt::global_heap;
-use std::uint;
 use std::unstable::intrinsics::{TyDesc, get_tydesc};
 use std::unstable::intrinsics;
 use std::util;

src/libstd/hashmap.rs

@@ -64,7 +64,6 @@ use num;
 use option::{None, Option, Some};
 use rand::Rng;
 use rand;
-use uint;
 use util::replace;
 use vec::{ImmutableVector, MutableVector, OwnedVector, Items, MutItems};
 use vec_ng;

src/libstd/str.rs

@@ -110,7 +110,6 @@ use ptr;
 use ptr::RawPtr;
 use to_str::ToStr;
 use from_str::FromStr;
-use uint;
 use vec;
 use vec::{OwnedVector, OwnedCloneableVector, ImmutableVector, MutableVector};
 use default::Default;