Upgrade Font Awesome to version 5 (#1446)

Upgrade Font Awesome to version 5 (SVG with JavaScript)

Close #1396

Merge branch 'release/3.0.0'

Merge branch 'feature/documentation-and-demo' into develop

Change "table of contents" default icon and text label

Expand on nav_list styles
- Consolidate SCSS partials

Merge branch 'feature/visual-refresh' into develop

Massage the grid layout

Continue to refine styles and layouts

Cleanup SCSS

Remove locale hash to shorten Liquid variable names

Add support for localizing UI text with a _data file

Merge branch 'feature/refactor-includes-layouts' into develop

Merge branch 'feature/refactor-layouts' into develop

Improve table of contents
- Replace html snippet with _includes/toc.html
- Add FA icon to table of contents header
- Display table of contents on small screens
- Add hierarchy to toc with indents