when creating a DOCTYPE use "html" lowercase by default instead of "HTML"

* HTMLparser.c: when creating a DOCTYPE use "html" lowercase
  by default instead of "HTML"
* parser.c xmlreader.c: optimization, gain a few % parsing speed by
  avoiding calls to "areBlanks" when not needed.
* include/libxml/parser.h include/libxml/tree.h: some structure
  extensions for future work on using per-document dictionaries.
Daniel
diff --git a/include/libxml/parser.h b/include/libxml/parser.h
index cb555ef..e52013b 100644
--- a/include/libxml/parser.h
+++ b/include/libxml/parser.h
@@ -237,8 +237,9 @@
     int                recovery;      /* run in recovery mode */
     int                progressive;   /* is this a progressive parsing */
     xmlDictPtr         dict;          /* dictionnary for the parser */
-    const xmlChar *   *atts;         /* array for the attributes callbacks */
+    const xmlChar *   *atts;          /* array for the attributes callbacks */
     int                maxatts;       /* the size of the array */
+    int                docdict;       /* use strings from dict to build tree */
 };
 
 /**