NWSAPI CSS Selector Engine

NWSAPI is a high-performance CSS selector engine, serving as a continuation and significant rework of the earlier `nwmatcher` project, currently at version 2.2.23. Its primary goal is to provide comprehensive and fast support for the latest CSS Level 4 Selectors, while also meticulously emulating native browser APIs such as `querySelector()`, `querySelectorAll()`, `matches()`, and `closest()`. The library is actively maintained, with a focus on continuous bug fixes and feature enhancements, and is intended to replace `nwmatcher` in environments like `jsdom`. NWSAPI differentiates itself through a unique architecture that employs regular expressions to parse CSS selector strings and metaprogramming to transform these into memoized JavaScript function resolvers, a process executed only once per selector for 'unmatched performances'. It ships with no external dependencies and supports both browser environments (via a global `NW.Dom` object) and headless environments like Node.js (as a CommonJS module).