bump crengine: new HTML parser, libRu and FB2 tweaks (#6560)

Includes:
- Revert "FB2: don't draw cover in scroll mode"
- (Upstream) FB2: fix coverpage drawing in scroll mode
- FB2 footnotes: only merge run-in when next is erm_final
- fb2.css: use OTF tabular-nums for footnote numbers
- Text: ignore ascii and unicode control chars
- Fix HR positionning when floats involved
- writeNodeEx(): minor tweaks
- OnTagClose(): add self_closing_tag parameter
- HTML format detection: accept HTML5 doctype
- HTML parser: rework Lib.ru specific handling
- HTML parser: new more conforming implementation
- HTML parser: ensure foster parenting inside tables

Also includes:
- SDL: don't bypass X11 WM compositor

frontend/document/credocument.lua

@@ -180,6 +180,10 @@ function CreDocument:requestDomVersion(version)
     cre.requestDomVersion(version)
 end
 
+function CreDocument:getDocumentFormat()
+    return self._document:getDocumentFormat()
+end
+
 function CreDocument:setupDefaultView()
     if self.loaded then
         -- Don't apply defaults if the document has already been loaded