Switched Tuple usage to KeyValuePair to support .NET35
Removed unused references from .csproj
Added project for .NET3.5 and accompanying unit test project.
Added NET35 build flag for conditional compilation for all test classes.
Moved the .nuspec file to the solution directory.
Added build configuration "NuGet" for automated packaging.
Added .net 4.0 project and accompanying unit test project.
Removed "NuGet" build configuration.
Added .net40 build to .nuspec file.