bump crengine: CSS parsing: cleanup and optimisations (#952)
bump crengine: CSS parsing: cleanup and optimisations (#952)

Includes:
- Fix background-image drawing overflowing page
- CSS parsing code: formatting cleanup and optimisations
Frenzie/koreader-base,koreader/koreader-base,koreader/koreader-base,NiLuJe/koreader-base,NiLuJe/koreader-base,Frenzie/koreader-base,koreader/koreader-base,NiLuJe/koreader-base,Frenzie/koreader-base,NiLuJe/koreader-base,koreader/koreader-base,Frenzie/koreader-base