Use 'const' keyword.
Use 'const' keyword.

As of rust-lang/rust@f9fc49c from two days ago, Rust has true constants.
Let's start using them.

bnoordhuis/v8.rs,bnoordhuis/v8.rs,tempbottle/v8.rs,Qard/v8.rs,bnoordhuis/v8.rs,tempbottle/v8.rs,bnoordhuis/v8.rs,bnoordhuis/v8.rs,tempbottle/v8.rs,bnoordhuis/v8.rs,tempbottle/v8.rs,tempbottle/v8.rs,tempbottle/v8.rs