Auto merge of servo#159 - CryZe:no-std, r=emilio

alloc is now stable

The alloc crate is now stable with 1.36. That means smallvec is now no_std compatible on stable Rust.

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lib.rs

@@ -29,7 +29,6 @@
 //! Note that this feature requires a nightly compiler (for now).
 
 #![cfg_attr(not(feature = "std"), no_std)]
-#![cfg_attr(not(feature = "std"), feature(alloc))]
 #![cfg_attr(feature = "union", feature(untagged_unions))]
 #![cfg_attr(feature = "specialization", feature(specialization))]
 #![cfg_attr(feature = "may_dangle", feature(dropck_eyepatch))]