crc64 2.0.0

CRC64 checksum implementation
Documentation
### 2.0.0 - 27. February 2022

* Remove UB/unsoundness internally
* Proper documentation
* Remove unused functionality

### 1.0.0 - 06. January 2016

* Implement Crc64 as a struct with Write (@seppo0010)

### 0.2.2 - 03. April 2015

* Use only stable features to run on Rust 1.0 Beta

### 0.2.1 - 23. January 2015

* Fix build issues with Rust nightly

### 0.2.0 - 23. January 2015

* Imense speedup thanks to Matt's crcspeed (https://matt.sh/redis-crcspeed)
* Updated to work with Rust 1.0
* Crate renamed: crc64-rs → crc64

### 0.1.0 - 22. November 2014

* Basic functionality