change `else if` to `else`
Merge pull request #9987 from wangsai/fix-typo

change `else if` to `else`
Fixes #9974

Added th selector in .table-row-variant mixin
Merge pull request #9999 from sqrt4/fix-9974

Fixes #9974
remove .btn-group

Removing this class--it's not used in the example and using it causes "bad things to happen." 

http://jsfiddle.net/josephtate/Jn6H4/
Merge pull request #10006 from jodytate/master

remove .btn-group