crossbeam-epoch 0.6.1

Epoch-based garbage collection
Documentation
# Version 0.6.1

- Update `crossbeam-utils` to `0.6`.

# Version 0.6.0

- `defer` now requires `F: Send + 'static`.
- Bump the minimum Rust version to 1.26.
- Pinning while TLS is tearing down does not fail anymore.
- Rename `Handle` to `LocalHandle`.
- Add `defer_unchecked` and `defer_destroy`.
- Remove `Clone` impl for `LocalHandle`.

# Version 0.5.2

- Update `crossbeam-utils` to `0.5`.

# Version 0.5.1

- Fix compatibility with the latest Rust nightly.

# Version 0.5.0

- Update `crossbeam-utils` to `0.4`.
- Specify the minimum Rust version to `1.25.0`.

# Version 0.4.3

- Downgrade `crossbeam-utils` to `0.3` because it was a breaking change.

# Version 0.4.2

- Expose the `Pointer` trait.
- Warn missing docs and missing debug impls.
- Update `crossbeam-utils` to `0.4`.

# Version 0.4.1

- Add `Debug` impls for `Collector`, `Handle`, and `Guard`.
- Add `load_consume` to `Atomic`.
- Rename `Collector::handle` to `Collector::register`.
- Remove the `Send` implementation for `Handle` (this was a bug). Only
  `Collector`s can be shared among multiple threads, while `Handle`s and
  `Guard`s must stay within the thread in which they were created.

# Version 0.4.0

- Update dependencies.
- Remove support for Rust 1.13.

# Version 0.3.0

- Add support for Rust 1.13.
- Improve documentation for CAS.

# Version 0.2.0

- Add method `Owned::into_box`.
- Fix a use-after-free bug in `Local::finalize`.
- Fix an ordering bug in `Global::push_bag`.
- Fix a bug in calculating distance between epochs.
- Remove `impl<T> Into<Box<T>> for Owned<T>`.

# Version 0.1.0

- First version of the new epoch-based GC.