Version 4.5.493 prerelease online

I have put a prerelease version (4.5.493) online via nuget and with an installer from www.cslanet.com

1. This version fixes an issue with .NET 4 and Silverlight with the nuget package for async.
2. It also adds a missing method to the IDataPortalActivator interface.
3. It adds a chm help file (in the installer) built using Sandcastle.

I am very hopeful that this is the last prerelease prior to the .500 release.