Rm unused feature

Author: Manishearth

src/libflate/lib.rs

@@ -25,7 +25,6 @@
        html_favicon_url = "http://www.rust-lang.org/favicon.ico",
        html_root_url = "http://doc.rust-lang.org/nightly/")]
 
-#![feature(core)]
 #![feature(int_uint)]
 #![feature(libc)]
 #![feature(staged_api)]