idna 0.5.0

IDNA (Internationalizing Domain Names in Applications) and Punycode.
Documentation
This Rust crate implements IDNA [per the WHATWG URL Standard](https://url.spec.whatwg.org/#idna). It also exposes the underlying algorithms from [*Unicode IDNA Compatibility Processing* (Unicode Technical Standard #46)](http://www.unicode.org/reports/tr46/) and [Punycode (RFC 3492)](https://tools.ietf.org/html/rfc3492). Quoting from [UTS #46’s introduction](http://www.unicode.org/reports/tr46/#Introduction): > Initially, domain names were restricted to ASCII characters. > A system was introduced in 2003 for internationalized domain names (IDN). > This system is called Internationalizing Domain Names for Applications, > or IDNA2003 for short. > This mechanism supports IDNs by means of a client software transformation > into a format known as Punycode. > A revision of IDNA was approved in 2010 (IDNA2008). > This revision has a number of incompatibilities with IDNA2003. > > The incompatibilities force implementers of client software, > such as browsers and emailers, > to face difficult choices during the transition period > as registries shift from IDNA2003 to IDNA2008. > This document specifies a mechanism > that minimizes the impact of this transition for client software, > allowing client software to access domains that are valid under either system.