Upgrade to current Rust

- libc is now outside std.
- global attributes changed to new syntax.
- nolink attributes are no longer valid.
Merge pull request #78 from bvssvni/rustup_20140409

Upgrade to current Rust
Update to current rust: libc is in its own crate.
Merge pull request #79 from mozilla-servo/rustup_20140410

Update to current rust: libc is in its own crate.
Allocate GL objects into Vecs, then slice for return

Since mozilla/rust@7d3b0bf we can't do this with primitive vectors
Merge pull request #80 from robn/vec-slice

Allocate GL objects into Vecs, then slice for return