Fast CSS Selectors API Engine

This is the "nwsapi" project, a continuation of the "nwmatcher" selector engine.

The objectives are the following:

• provide complete support for the latest CSS Level 4 Selectors and improve on speed
• emulate native browsers API querySelector(), querySelectorAll(), matches() and closest()
• maintain extra functionalities found in the original "nwmatcher", especially the "callback" feature
• replace current "nwmatcher" support in "jsdom" and provide continuous maintenance and bugfixes