- `std::fmt::WriteError` is now `std::fmt::Error`.
- abandoned rust-ci for documentations (sorry, but it didn't work
nowdays ;_;), we are now publishing directly to Github pages.
- added a new example.
- reexported all public APIs in the crate root.
- made all constructors fail on the invalid arguments by default;
`*_opt()` variants have been added for the original behavior.
- same for `DateZ::{succ,pred}`.
- fixed a missing overflow check from `TimeZ::from_hms_{milli,micro}`.
Kang Seonghoon