public void parseFile(final Uri uri, final String readOnlyContext) {
        parseFile(uri, readOnlyContext, null);
    }
add a new lookup-value for the given name to the given lookupData array.
If no array is given (null value passed), the value is added to
the context-binded array. In that case, unknown names and values are
created dynamically.

@return a newly created value element, if any, to optionally add aliases
main/src/main/java/cgeo/geocaching/brouter/expressions/BExpressionContext.java