2.4.0-alpha.1

Additions:

• feat: Add option restoreScroll
• doc: add more info on testing hidden regions
• feat: add S.C. 2.4.4 to link-name rule. Fixes #369
• feat: Add Japanese localisation
• doc: Add instructions on debugging on CircleCI
• test: add unit tests for button-has-visible-text
• chore: add descriptions to Grunt tasks
• feat(aria): Support progressive ARIA 1.1 attributes / roles
• feat: Add new ARIA 1.1 values for haspopup
• feat: Add aria-orientation to additional roles

Changes:

• chore: add help text for testconfig Grunt task
• fix: Properly output error stack
• doc: Add 'on mobile' to viewport rule
• fix: Ensure all tests pass in Chrome
• fix: Minimise scrolling in getBackgroundColor
• chore: Minor build chores for whitespace and lockfile
• fix: Align impact levels with Deque Way
• fix: Set relatedNodes on color/link-in-block rules
• fix: incomplete results should have impact
• fix(aria): Allow implicit attribute values
• chore: ignore growl in retire
• fix: Use getAttribute(id) over .id
• fix: Exclude any checks from output if one passed
• fix(aria): Treegrid should own rows, not treeitems
• fix(aria): add exception for native input combobox missing textbox. Fixes #160
• test: fix aria/required-children for jshint
• feat: allow link text from single-cell layout table
• fix: expand tr support for color contrast
• chore: ignore node_modules in examples when linting