Remove most of FlowList

This needs to be reworked for DST.  Until then, DList<FlowRef> will do.
Upgrade to rustc 0.12.0-pre (4d2af3861 2014-09-17 15:51:11 +0000)
Update the CEF port
Eliminate warnings
Fix upstream merge fallout
Use upstream lazy_static!() macro through Cargo

... instead of having our own copy.

https://github.com/Kimundi/lazy-static.rs
Merge pull request #3438 from servo/rustup

Upgrade Rust