ZipWriter: allow for storing files uncompressed (#591)
ZipWriter: allow for storing files uncompressed (#591)


NiLuJe/koreader-base,Frenzie/koreader-base,houqp/koreader-base,koreader/koreader-base,houqp/koreader-base,NiLuJe/koreader-base,houqp/koreader-base,koreader/koreader-base,NiLuJe/koreader-base,Frenzie/koreader-base,Frenzie/koreader-base,houqp/koreader-base,Frenzie/koreader-base,NiLuJe/koreader-base,koreader/koreader-base,koreader/koreader-base