#199 XML Parser doesn't handle extra components

[James Agnew]

Filing this bug to document a checkin-

The CX datatype has 3 children. If the pipe parser encounters extras, it parses them successfully, but the XML parser ignores them, eg in the following example HD.4 and HD.5 are ignored.

    <MSH.3>
        <HD.2>OLIS</HD.2>
        <HD.3>X500</HD.3>
        <HD.4>HD.4</HD.4>
        <HD.5>HD.5</HD.5>
    </MSH.3>

This is now fixed so that they are parsed as they are for the pipe parser

Thanks to Ryan Baldwin for diagnosing this.