cleanup the output buffer support to at least get the basic to work fixes

* python/generator.py python/libxml.c python/libxml_wrap.h:
  cleanup the output buffer support to at least get the basic
  to work
* python/tests/outbuf.py python/tests/serialize.py: fixes and
  cleanup.
* include/libxml/xmlwriter.h: cleanup
Daniel
diff --git a/python/tests/serialize.py b/python/tests/serialize.py
index d7226c4..5b969a9 100755
--- a/python/tests/serialize.py
+++ b/python/tests/serialize.py
@@ -69,19 +69,19 @@
 #
 doc = libxml2.htmlParseDoc("""<html><head><title>Hello</title><body><p>hello</body></html>""", None)
 str = doc.serialize()
-if str != """<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+if str != """<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
 <html><head><title>Hello</title></head><body><p>hello</p></body></html>
 """:
    print "error serializing HTML document 1"
    sys.exit(1)
 str = doc.serialize("ISO-8859-1")
-if str != """<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+if str != """<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
 <html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Hello</title></head><body><p>hello</p></body></html>
 """:
    print "error serializing HTML document 2"
    sys.exit(1)
 str = doc.serialize(format=1)
-if str != """<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+if str != """<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
 <html>
 <head>
 <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
@@ -93,7 +93,7 @@
    print "error serializing HTML document 3"
    sys.exit(1)
 str = doc.serialize("iso-8859-1", 1)
-if str != """<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+if str != """<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
 <html>
 <head>
 <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">