3.0.0-alpha.1 (Shadow DOM)

Changes:

• Shadow DOM support: rules and checks now supply a virtualNode in addition to the light DOM node. No slot styling support until supported by Chrome
• All commons and utilities refactored to support Shadow DOM
• Tests all refactored to support Shadow DOM
• API docs and developer guide now cover developing for Shadow DOM
• Fix for impact of incomplete nodes (#356)
• Fix for combobox false positive (#160)

Additions:

• Commons virtual methods for handling virtual DOM
• New axe.utils.querySelectorAll method for querying the flattened tree
• New core APIs and test utilities for Shadow DOM development
• Support for ARIA 1.1: role=feed, role=term, aria-placeholder, aria-modal,
  aria-current, aria-keyshortcuts, role=treegrid, aria-orientation, aria-haspopup