Demo: changing input math language should show the converted equation in the new language

[ronaldtse]

By default the equation is in language "AsciiMath":

sum_(i=1)^n i^3=((n(n+1))/2)^2

When I change the input language to "MathML", it should show:

<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mstyle displaystyle="true">
    <mrow>
      <munderover>
        <mo>&#x2211;</mo>
        <mrow>
          <mi>i</mi>
          <mo>=</mo>
          <mn>1</mn>
        </mrow>
        <mi>n</mi>
      </munderover>
      <msup>
        <mi>i</mi>
        <mn>3</mn>
      </msup>
    </mrow>
    <mo>=</mo>
    <msup>
      <mrow>
        <mo>(</mo>
        <mfrac>
          <mrow>
            <mi>n</mi>
            <mrow>
              <mo>(</mo>
              <mi>n</mi>
              <mo>+</mo>
              <mn>1</mn>
              <mo>)</mo>
            </mrow>
          </mrow>
          <mn>2</mn>
        </mfrac>
        <mo>)</mo>
      </mrow>
      <mn>2</mn>
    </msup>
  </mstyle>
</math>