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
6 files changed