Platform check for Mono and Windows

Platform.cs

/// <summary>
/// Helper methods for determining the platform.
/// </summary>
public static class Platform
{
    /// <summary>
    /// Gets if the platform is Windows NT or later.
    /// </summary>
    public static bool IsWindows
    {
        get
        {
            return (Environment.OSVersion.Platform == PlatformID.Win32NT);
        }
    }

    /// <summary>
    /// Gets if the platform is Mono on Unix or Mac.
    /// </summary>
    public static bool IsMono
    {
        get
        {
            var platform = (int)Environment.OSVersion.Platform;
            return (platform == 4 /* Unix */ || platform == 6 /* MacOSX */ || platform == 128 /* Legacy */);
        }
    }
}