bump crengine: text selection tweaks and helpers

Includes:
- lvtext: fix m_kerning_mode type
- XML: let 'gb2312' (Chinese) encoding be known
- Add ldomXPointer::getChar()
- LVDocView::getNodeByPoint(): tweak for text selection
- Fonts: allow fetching the list of embedded fonts
cre.cpp:
- getTextFromPositions(): use getNodeByPoint(forTextSelection=true)
  to allow panning in margins and get the nearest text instead
  of nothing.
- add extendXPointersToSentenceSegment() to allow extending some
  xpointer range to include punctuations at start or end (with
  for now a quite rudimentory implementation).
- add getEmbeddedFontList() to allow fetching the list of
  embedded fonts in the current EPUB book.

frontend/apps/reader/modules/readerview.lua

@@ -258,8 +258,6 @@ function ReaderView:screenToPageTransform(pos)
         end
     else
         pos.page = self.document:getCurrentPage()
-        -- local last_y = self.document:getCurrentPos()
-        logger.dbg("document has no pages at", pos)
         return pos
     end
 end