Fix encoding <> in upnp messages

[Petr Nejedly]

<?xml version="1.0" encoding="utf-8" ?><SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"><SOAP-ENV:Body><u:BrowseResponse xmlns:u="urn:schemas-upnp-org:service:ContentDirectory:1"><Result><?xml version="1.0" encoding="UTF-8" standalone="no"?><DIDL-Lite xmlns="urn:schemas-upnp-org:metadata-1-0/DIDL-Lite/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dlna="urn:schemas-dlna-org:metadata-1-0/" xmlns:upnp="urn:schemas-upnp-org:metadata-1-0/upnp/"><container childCount="7" id="A" parentID="0" restricted="1"><dc:title>Audio</dc:title><upnp:class>object.container</upnp:class></container><container childCount="5" id="I" parentID="0" restricted="1"><dc:title>Image</dc:title><upnp:class>object.container</upnp:class></container><container childCount="10" id="V" parentID="0" restricted="1"><dc:title>Video</dc:title><upnp:class>object.container</upnp:class></container></DIDL-Lite></Result><NumberReturned>3</NumberReturned><TotalMatches>3</TotalMatches><UpdateID>1</UpdateID></u:BrowseResponse></SOAP-ENV:Body></SOAP-ENV:Envelope>

[Petr Nejedly]

This is correct regarding to ContentDirectoryService spec (2.5.4):

Note that since the DIDL-Lite format of Result is based on XML, it needs to be escaped (using the normal XML rules: [XML] Section 2.4 Character Data and Markup) before embedding in a SOAP response message.