Fixed nested tab elements li activation

Added closest li instead of direct parent so that you can nest multiple elements within tabs, such as button groups
Merge pull request #13191 from AshleyDawson/master

Fixed nested tab elements li activation
versions
grunt dist
Merge pull request #13578 from twbs/fat-versions

versions
grunt for raw js
Merge branch 'master' of github.com:twbs/bootstrap
grunt
grunt
no more concurrency