[CUETools] Update UnRAR DLLs

- Update UnRAR DLLs to v5.90.1
  The previous version used by CUETools was 3.80
- This adds support for newer RAR files using RAR5 format.
  Fixes the following error, when opening a RAR5 file:
    Exception: File is not a valid archive.
- Use DLLs from current UnRARDLL.exe [1] and rename according to the
  filenames used by CUETools so far:
    UnRAR.dll -> cuetools.net\ThirdParty\Win32\unrar.dll
    x64\UnRAR64.dll -> cuetools.net\ThirdParty\x64\Unrar.dll
  Remark: The capital U in Unrar.dll for x64 is intentional.
- Update Unrar.cs:
  New RHDF_DIRECTORY (0x20) flag in RARHeaderData and RARHeaderDataEx
  structures indicates the directory entry.
  Info from UnRARDLL.exe\whatsnew.txt (24 December 2012).
- Remove unneeded file CUETools\unrar.dll (32-bit, v3.80) and remove
  associated unrar.dll Content entry from CUETools\CUETools.csproj

[1] https://www.rarlab.com/rar/UnRARDLL.exe

CUETools/CUETools.csproj

@@ -321,8 +321,6 @@
     <None Include="Resources\wma.ico" />
     <None Include="Resources\more\card--pencil.png" />
     <Content Include="Resources\opus.ico" />
-    <Content Include="unrar.dll">
-    </Content>
     <Content Include="Resources\accuraterip_16.bmp" />
     <None Include="Resources\ape.ico" />
     <Content Include="Resources\AR.ico" />