update to latest rust

[kstep]

• [deriving] -> #[derive]

• ToPrimitive/FromPrimitive not in prelude
• [mut] syntax doesn't work to provide mut slice
• Formatter::write() -> Formatter::write_str()
• hash_map::Entries -> hash_map::Iter

• ![feature(old_orphan_check)]

• channel/Sender/Receiver not in prelude and return Result

[chris-morgan]

Thanks for that! A bit of a pity about old_orphan_check, but it looks like #[deriving(Hash)] on Method currently requires it, so it can stay around for the moment.

[kstep]

Yes, it's a shame. Also, FYI, #[derive(RustcEncoding)] doesn't work without old_orphan_check too.