Upgrade iron and its libs.

Note logger is my fork for now. Hopefully those changes will be merged.

$ ./versions.sh
rustc 0.12.0-pre-nightly (5419b2ca2 2014-08-29 22:16:20 +0000)
cargo 0.0.1-pre-nightly (64156a3 2014-08-29 19:04:34 +0000)