language updates and the initial attempt to use travis.

- Makefile changes for the recent rustc changes on -o.
- IoResult everywhere.
- earlyexit! is gone (in favor of built-in if_ok!).
  util/macros.rs is kept for later use.
- removed the use of std::borrow::ref_eq.
- libextra is no longer used in favor of libcollections and libsync.
- std::fmt::Default becomes std::fmt::Show.