Support mixed content for XML imports

Complex types can define their content to be mixed. This means that an element has both text and child elements as contents. We would like Mendix to support mixed content.

Example:

<Response>
  <Result>
    <Channel>
      <Products>
        <Product id="1">
          <Fields>
            <Field name="ArticleGroup">1</Field>
            <Field name="ImageUrl">
              <Value>First value</Value>
              <Value>Second value</Value>
            </Field>
          </Fields>
        </Product>
        <Product id="2">
          <Fields>
            <Field name="ArticleGroup">2</Field>
            <Field name="ImageUrl">Just one value</Field>
          </Fields>
        </Product>
      </Products>
    </Channel>
  </Result>
</Response>