Remove work-around for Rust issue 16597.

rust-lang/rust#16597

Author: SimonSapin

src/lib.rs

@@ -7,9 +7,6 @@
 
 #![feature(globs, macro_rules)]
 
-// Temporary work-around for https://github.com/rust-lang/rust/issues/16597
-#![feature(import_shadowing)]
-
 extern crate encoding;  // https://github.com/lifthrasiir/rust-encoding
 
 extern crate debug;