libxml++: New API in libxml++ 2.24

# New API in libxml++ 2.24

Member xmlpp::Element::add_child_text (xmlpp::Node* previous_sibling, const Glib::ustring& content=Glibustring())

Member xmlpp::Element::add_child_text_before (xmlpp::Node* next_sibling, const Glib::ustring& content=Glibustring())

Member xmlpp::Node::add_child (xmlpp::Node* previous_sibling, const Glib::ustring& name, const Glib::ustring& ns_prefix=Glibustring())

Member xmlpp::Node::add_child_before (xmlpp::Node* next_sibling, const Glib::ustring& name, const Glib::ustring& ns_prefix=Glibustring())

Member xmlpp::SaxParser::parse_chunk_raw (const unsigned char* contents, size_type bytes_count)

Class xmlpp::Schema

Class xmlpp::SchemaValidator