IE9, IE10, IE11 ignore CSS rem units in the line-height property

https://connect.microsoft.com/IE/feedback/details/776744/css3-using-rem-to-set-line-height-in-before-after-pseudo-elements-doesnt-work
Merge pull request #799 from arleytriana/patch-4

IE9, IE10, IE11 ignore CSS rem units in the line-height property