fix handling of empty CDATA nodes as reported and discussed around #514181

* xmlsave.c parser.c: fix handling of empty CDATA nodes as 
  reported and discussed around #514181 and associated patches
* test/emptycdata.xml result/emptycdata.xml* 
  result/noent/emptycdata.xml: added a specific test in the
  regression suite.
Daniel

svn path=/trunk/; revision=3701
diff --git a/result/emptycdata.xml.sax b/result/emptycdata.xml.sax
new file mode 100644
index 0000000..39587c6
--- /dev/null
+++ b/result/emptycdata.xml.sax
@@ -0,0 +1,10 @@
+SAX.setDocumentLocator()
+SAX.startDocument()
+SAX.startElement(html, xmlns='http://www.w3.org/1999/xhtml')
+SAX.characters(
+, 1)
+SAX.pcdata(, 0)
+SAX.characters(
+, 1)
+SAX.endElement(html)
+SAX.endDocument()