Merge pull request #38 from larsbergstrom/rustup_20140410b

Rust upgrade
Merge pull request #39 from mozilla-servo/rustup_20140510

Android Rust Upgrade fixes
Fix some deprecated warnings for to_owned()
Merge pull request #40 from mozilla-servo/string-warn

Fix some deprecated warnings for to_owned()
Update ~str/String, to_owned/to_string, & cast/mem.