Fix CHTML.getNode() to handle nested tags, and fix CHTMLchildNode() for munderover and msubsup elements.  Resolves issue #1360
Fix CHTML.getNode() to handle nested tags, and fix CHTMLchildNode() for munderover and msubsup elements.  Resolves issue #1360

GerHobbelt/MathJax,jinntrance/mathjax,thomasjm/MathJax,GerHobbelt/MathJax,thomasjm/MathJax,jinntrance/mathjax,wikimedia/MathJax,dpvc/MathJax,thomasjm/MathJax,thomasjm/MathJax,thomasjm/MathJax