Deny unsafe blocks in script.

As a first start, this allows them indiscriminately where used.

components/script/script_task.rs

@@ -5,6 +5,8 @@
 //! The script task is the task that owns the DOM in memory, runs JavaScript, and spawns parsing
 //! and layout tasks.
 
+#![allow(unsafe_blocks)]
+
 use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::DocumentBinding::{DocumentMethods, DocumentReadyState};
 use dom::bindings::codegen::Bindings::EventBinding::EventMethods;