Remove unused imports

I was able to remove unused imports, and fix the following warnings

src/libstd/hashmap.rs:23:15: 23:23 warning: unused import [-W unused-imports (default)]
src/libstd/task/spawn.rs:95:15: 95:23 warning: unused import [-W unused-imports (default)]
src/libstd/rt/uv/mod.rs:42:0: 42:9 warning: unused import [-W unused-imports (default)]
src/libstd/rt/uv/mod.rs:45:0: 45:9 warning: unused import [-W unused-imports (default)]
src/librustc/middle/trans/meth.rs:26:0: 26:26 warning: unused import [-W unused-imports (default)]
src/librustc/back/link.rs:210:20: 210:25 warning: unused import [-W unused-imports (default)]

I was unable to fix the following unused import warnings. The code
here was weird.

src/libextra/std.rc:40:11: 40:14 warning: unused import [-W unused-imports (default)]
src/libextra/std.rc:40:16: 40:24 warning: unused import [-W unused-imports (default)]

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libstd/task/spawn.rs b/src/libstd/task/spawn.rs
index 780e9d6d923..30ad4ee2a89 100644
--- a/src/libstd/task/spawn.rs
+++ b/src/libstd/task/spawn.rs
@@ -92,7 +92,7 @@ use uint;
 use util;
 use unstable::sync::{Exclusive, exclusive};
 use rt::local::Local;
-use iterator::{Iterator, IteratorUtil};
+use iterator::{IteratorUtil};
 
 #[cfg(test)] use task::default_task_opts;
 #[cfg(test)] use comm;