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
10 files changed