NuGet Support

I have added a nuspec file for generating a NuGet package to be submitted to http://nuget.org. To create the package:

1. Ensure [NuGet.exe](https://nuget.codeplex.com/releases/view/58939) is in your path
2. Build the project with the *Release* configuration
3. Open **cmd** to the *csproj* directory
4. Execute the following command to create a NuGet Package: `nuget.exe pack -Properties Configuration=Release`
5. Upload the output *.nupkg* to http://nuget.org.

These changes resolve issue #7