This avoids having consumers import libc for common signals, and it
improves discoverability since users need not be aware that libc
contains all supported constants.
* Denied all warnings in tests, and denied rust_2018_idioms violations
* Bumped the crate version and set publish = false
* Pruned dependencies:
- Only pull in tokio-sync on windows where it is used
- Removed unused dev-dependencies
* Switch to Async{Read, Write} traits from tokio-io rather than
futures-io
* Use #[tokio::test] where possible
* Removed deprecated items
* Fix all doc examples
Ivan Petkov