Updated the tooltip plugin to add WAI-ARIA attributes to associate to element
Cleaning the style of the tooltip unit tests added.

- Followed the coding styles.
- Recompiled everything.
move Grunt info from README into HTML docs

Fixes #13470
Update .travis.yml
Remove outdated rtl nav links
Customizer: make utilities.less inclusion mandatory

Fixes #13305.
Pulling in the last changes for the pullrequest  will fix them soon
Adding the addditional unit test