## Changelog

* Version 0.2.1
  * added implementations for `std::rc::Weak` and `std::sync::Weak`
  * added `ByIdDeref` wrapper
* Version 0.2.0
  * renamed `RefId` to `ById`
  * use new trait `Id` to determine identity, instead of `Deref` and pointer comparison
* Version 0.1.0
  * derive Copy for RefId
* Version 0.0.3
  * minor fix in documentation
* Version 0.0.2
  * support smart pointers (through `Deref`)
* Version 0.0.1