Highlighting/xmlrefactor

Now xml highligth rules handle multiline doctype with embedded declarations, multiline processing instructions.
All tag embedding logic is included in XmlHighlightRules.prototype.embedTagRules().
HTML rules are inherited from XML with some overriding.
All HTML mixed rules now just extend HTML ones.

Push/pop state is great feature. By the way what about moving normalizeRules logic into tokenizer (at least push/pop) ?