ElementaryMathExamples-mstack17

test for : mstack align="top -4"

W3C sample	WIRIS
	$010111\mathrm{zzzzz}$

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <mstack align="top -4">
    <msline/>
    <mn>010</mn>
    <msline/>
    <mn>111</mn>
    <msline/>
  </mstack>
  <mi>zzzzz</mi>
</math>

Author: Yecheng Gu