Fix CD problems by using breadth-first search in getNode().  Resolves #1691.
Fix CD problems by using breadth-first search in getNode().  Resolves #1691.

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