Fixed issue with .perspectiveUpRetourn and corrected spelling of class names

I fixed some issues with the Magic CSS library. My first commit of this fork was a typo and it should be "Fixed issue with .perspectiveUpRetourn". The CSS class perspectiveUpReturn wasn't working because the backface-visibility property was incorrectly placed. I fixed the class properties and also renamed all instances of Retourn to Return (which I assume is what you wanted them to be called). I re-compressed the fixed stylesheet and corrected all the spellings of Return in magic.styl as well.