This batch of changes upgrades Servo to work with the Rust upgrade as of
April 10, 2014. The main changes are to privacy, to work around the
issues with incorrect bounds on the libstd `Arc<Mutex<T>>`, and the
various API changes strewn throughout the libraries.
auto merge of #2238 : mozilla/servo/rustup_20140410c, r=Ms2ger

r? @metajack 

Note that all pending submodule PRs must be landed before this should be given r+.