Visibility Fix for IE8/9/10

Fixes always displayed IE8 issue, fixes IE9/10 Hovering issue
Set visibility for persistant tooltip also.
Also add comment for using visibility CSS property.
Minor fixes and additions.
- add IE10 to pseudo element transition supported list
- add "Who's using it sections"
- typos
- link the license
- Correct the lib description
bump patch and update lib
[v1.2.1] Merge branch 'dev'