xmlTextConcat works with comments and PI nodes (bug #355962). fix

* tree.c: xmlTextConcat works with comments and PI nodes (bug #355962).
* parser.c: fix resulting tree corruption when using XML namespace
  with existing doc in xmlParseBalancedChunkMemoryRecover.
diff --git a/tree.c b/tree.c
index 26e5abd..07a555a 100644
--- a/tree.c
+++ b/tree.c
@@ -6529,7 +6529,9 @@
     if (node == NULL) return(-1);
 
     if ((node->type != XML_TEXT_NODE) &&
-        (node->type != XML_CDATA_SECTION_NODE)) {
+        (node->type != XML_CDATA_SECTION_NODE) &&
+	(node->type != XML_COMMENT_NODE) &&
+	(node->type != XML_PI_NODE)) {
 #ifdef DEBUG_TREE
 	xmlGenericError(xmlGenericErrorContext,
 		"xmlTextConcat: node is not text nor CDATA\n");