.tar.7z support

[SupinePandora43]

stacktrace:

SharpCompress.Compressors.LZMA.DataErrorException: Data Error
   at SharpCompress.Compressors.LZMA.LzmaStream.Read(Byte[] buffer, Int32 offset, Int32 count)
   at SharpCompress.Compressors.LZMA.Utilites.Utils.ReadExact(Stream stream, Byte[] buffer, Int32 offset, Int32 length)
   at SharpCompress.Common.SevenZip.ArchiveReader.ReadAndDecodePackedStreams(Int64 baseOffset, IPasswordProvider pass)
   at SharpCompress.Common.SevenZip.ArchiveReader.ReadDatabase(IPasswordProvider pass)
   at SharpCompress.Archives.SevenZip.SevenZipArchive.LoadFactory(Stream stream)
   at SharpCompress.Archives.SevenZip.SevenZipArchive.LoadEntries(IEnumerable`1 volumes)
   at SharpCompress.Archives.AbstractArchive`2..ctor(ArchiveType type, SourceStream srcStream)
   at SharpCompress.Archives.SevenZip.SevenZipArchive..ctor(SourceStream srcStream)
   at SharpCompress.Archives.SevenZip.SevenZipArchive.Open(FileInfo fileInfo, ReaderOptions readerOptions)
   at SharpCompress.Archives.SevenZip.SevenZipArchive.Open(String filePath, ReaderOptions readerOptions)

file in question: ultralightcore-bin-41a04e01-linux-x64.7z
file sha256: c6dd7e4ba5867fe763109263a5af8da40cf3e5cf46b91e4892eac76a49ec0746

code to replicate:

SevenZipArchive.Open(file);

for some reason, i can't open it in Ark, but can in Dolphin 😕
Turns out it's .tar.7z archive!

[adamhathcock]

should easy to add to detection alongside gzip and bzip2

[btomblinson]

Pull request #763 closes this