Switch to using public release of TorSharp

[kzu]

All our required PRs have been merged:

• Bump .NET Framework to newest supported TFM joelverhagen/TorSharp#79
• Use tor-win64 when running on X64 Windows joelverhagen/TorSharp#78
• Add support for configuring HttpTunnelPort for Tor joelverhagen/TorSharp#77
• Separate Configure from Start joelverhagen/TorSharp#72

So we don't need the fork anymore :)