Added png compression task

```
Running "pngmin" task
>> Compressed 8 files
>> Uncompressed size: 186kb, Compressed size: 25.76kb, Savings: 86.15%
```
Share: All panel and link markup now auto-generated
Merge pull request #3724 from pjackson28/fixshare

Share: All panel and link markup now auto-generated
Fixed mistaken replacements with 'panel'.
Overlay: Added escape handling
Merge pull request #3726 from pjackson28/addescapetooverlay

Overlay: Added escape handling
Merge pull request #3725 from thomasgohard/fix-share-panel-replacements

Share: Fixed mistaken replacements with 'panel'
Merge pull request #3727 from EricDunsworth/v4.0-broken-link-fixes

Tabs & multimedia: Fixed various wrong/broken links in HBS files.
Accessibility Responsiblity Breakdown: Added option to limit the number of visible entries (fixes #3721)
Merge pull request #3730 from pjackson28/arboption

Accessibility Responsiblity Breakdown: Added option to limit the number of visible entries (fixes #3721)
Overlay: Added overflow: auto and max-height: 100% to resolve issue with overlay being taller than the viewport
Merge pull request #3731 from pjackson28/improveoverlay

Overlay: Added overflow: auto and max-height: 100% to resolve issue with overlay being taller than the viewport
Overlays: Shortened some of the class names
Merge pull request #3732 from pjackson28/improveoverlay

Overlays: Shortened some of the class names
Overlays: Now returns focus to the triggering link when overlay closed
Merge pull request #3733 from pjackson28/overlaytweaks

Overlays: Now returns focus to the triggering link when overlay closed
Overlays: Fixed keyboard handling for second time panel is opened
Merge pull request #3734 from pjackson28/overlaychanges

Overlays: Fixed keyboard handling for second time panel is opened
Overlays: Added basic aria-hidden support and outside activity handling
Merge pull request #3735 from pjackson28/overlaysaria

Overlays: Added basic aria-hidden support and outside activity handling