rustc-ap-serialize 200.0.0

Automatically published version of the package `serialize` in the rust-lang/rust repository from commit 4f3c7a472b77ba3f3afbc12d004b9d1bbcee7fe7 The publishing script for this crate lives at: https://github.com/alexcrichton/rustc-auto-publish

Support code for encoding and decoding types.