Make mrows that are embellished operators properly include the elements other than the core when stretched.  Resolves issue #775.
Make mrows that are embellished operators properly include the elements other than the core when stretched.  Resolves issue #775.

nvp2211/MathJax,thomasjm/MathJax,anueshenxing/MathJax,cben/MathJax,Edraak/MathJax,Ivanwangcy/MathJax,Ivanwangcy/MathJax,GerHobbelt/MathJax,Edraak/MathJax,jeremykenedy/MathJax,anusornc/MathJax,thomasjm/MathJax,mcanthony/MathJax,thomasjm/MathJax,mcanthony/MathJax,cheerfulstoic/MathJax,cben/MathJax,thomasjm/MathJax,minrk/components-mathjax,ManrajGrover/MathJax,jinntrance/mathjax,minrk/components-mathjax,wikimedia/MathJax,anueshenxing/MathJax,anusornc/MathJax,minrk/mathjax-component,nvp2211/MathJax,GerHobbelt/MathJax,thomasjm/MathJax,jeremykenedy/MathJax,cheerfulstoic/MathJax,jinntrance/mathjax,perseoq/MathJax,physikerwelt/MathJax,ManrajGrover/MathJax,minrk/mathjax-component,perseoq/MathJax,rachetfoot/MathJax,dpvc/MathJax