Optimised the overlays CSS.
Added overlay demo page.
Removed overlay-specific CSS from Share widget now that it's been included in the overlay CSS.
reworked menu system

corrected variable import and restructed the SCSS
Focus: Changed event to setfocus.wb and added test and helper for same page link focus changes
Merge pull request #3672 from pjackson28/linkclickfocus

Focus: Changed event to setfocus.wb and added test and helper for same page link focus changes
Added check to ensure that any specified height is overriden before calculating the heights.
Focus: Improved compatibility of same page links test with other WET plugins
Merge pull request #3676 from pjackson28/optimizesamepagehandling

Focus: Improved compatibility of same page links test with other WET plugins
Focus: Added Chrome/Safari focus fix for deep linking (fixes #3083)
Merge pull request #3677 from pjackson28/adddeeplinkhelp

Focus: Added Chrome/Safari focus fix for deep linking (fixes #3083)
Merge pull request #3675 from thomasgohard/fix-equalheight-override-static-height

[Equal heights] Override specified height before calculating heights
Toggle: refactored group toggle and fixed details click

* Group toggle code  now sets on/off CSS classes and data states
  on the grouped elements.
* event.target for details element clicks was referencing the nested
  summary element.  Fixed by passing reference to clicked details
  element.
Toggle: added Accordion example using group toggle
Details: added toggle.wb-details event

* New event allows toggle plugin to open/close polyfilled details
  elements without triggering a summary click.
* Events that open/close details elements are now allowed
  to propagate.
Merge pull request #3668 from masterbee/menuadjustment

MENU: Reworked logic flow and optimized imports
Added header to overlays.
Merge pull request #3681 from patheard/toggle-group

Toggle: group toggle updates and accordion example
Merge pull request #3683 from thomasgohard/plugin-overlay

Improvements to overlay plugin
Fixed the markup for the share widget's overlay.