*
     * This method removes characters that are not allowed in XML documents
     * according to the XML 1.0 specification. Valid characters include:
     * - Tab (0x9)
     * - Line feed (0xA)
     * - Carriage return (0xD)
     * - Any character between 0x20 and 0xD7FF
     * - Any character between 0xE000 and 0xFFFD
     * - Any character between 0x10000 and 0x10FFFF
     *

    /**
     * UTF-7 Byte Order Mark definition.
     */
    protected static final ByteOrderMark BOM_UTF_7 = new ByteOrderMark("UTF-7", 0x2B, 0x2F, 0x76);

    /**
     * HTML4 unescape translator.
     */
    protected static final CharSequenceTranslator UNESCAPE_HTML4 = new AggregateTranslator(

        <match value="0x4" type="big32" offset="4"/>
        <match value="0x5" type="big32" offset="4"/>
        <match value="0x6" type="big32" offset="4"/>
        <match value="0x7" type="big32" offset="4"/>
        <match value="0x8" type="big32" offset="4"/>
        <match value="0x9" type="big32" offset="4"/>
        <match value="0xA" type="big32" offset="4"/>
        <match value="0xB" type="big32" offset="4"/>