`PackageReaderOptions.SkipManifestItemsWithDuplicateIds` property may be missing

[KKatationer]

I had some errors say that something is not unique.

https://github.com/vers-one/EpubReader/blob/master/Source/VersOne.Epub/Readers/PackageReader.cs#L176

#95
I can not find this property from source code you mentioned above.
And it may also be necessary to add a PackageReaderOptions.SkipManifestItemsWithDuplicateHrefs property.

Some of the checksum functions can be ignored because of the mixed quality of programs that generate epub files, as long as the results are presented well in the end.

Thanks for your work on this project and looking forward to your next version!

OutControl.zip

[vers-one]

Issue #95 is not implemented yet, I'm still working on it.