(raptor_xml_writer_start_element_common): attribute namespaces [coverity CID 29244]

(raptor_xml_writer_start_element_common): Process attribute
namespaces only if there is a namespace stack [coverity CID 29244]
(end_element): Do not call rdfa_complete_list_triples() with no new subject [coverity CID 29254]
(raptor_rdfxml_serialize_statement): Restore *name always [coverity CID 29255]
Treat raptor_iostream_read_bytes() returning int [coverity CID 29256]

(raptor_parser_parse_iostream): Treat raptor_iostream_read_bytes()
return as int, convert to size_t when it's known to be non-negative.
[coverity CID 29256]

The real fix is incompatible API change to make iostream return
size_t or ssize_t for reads.
(test_read_from_filename): Use int for read bytes values
Check return of raptor_xml_escape_string for errors [coverity CID 29258]

(raptor_namespace_format_as_xml): Check return values of
raptor_xml_escape_string() for negative failure before casting to
size_t.
(rdfa_complete_list_triples):  strdup and strstr output. [coverity CID 29260]

(rdfa_complete_list_triples): Be careful for strdup and strstr
returning NULL. [coverity CID 29260]
(rdfa_resolve_uri): Check end_index2 is not NULL [coverity CID 29261]
(raptor_rss10_emit_rdfxml_item_triples): root_element NULL [coverity CID 34616]

(raptor_rss10_emit_rdfxml_item_triples): start xml root_element if not NULL [coverity CID 34616]