bump crengine: minor fixes (ruby, a crash, non-linear flows)

[poire-z]

Includes https://github.com/koreader/crengine/pull/565 :

• html5.css: really ensure ruby centering
• getRenderedWidths(): fix possible crash with 0-width images
• Page splitting: ignore empty non-linear flows
• LvDocView header: allow overriding "page/total %"

cre.cpp: add setPageInfoOverride() to allow tweaking top status bar display of page number/count/%.

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This change is 

[benoit-pierre]

Yes.