Some updates

I added a few moreĀ items to the Known Issues page.

Also, a new page added: Calling Help Viewer 1.0 from VS add-in code. If you're developing add-ins for Visual Studio 2010 (or earlier actually), you may find this information handy. It describes the references necessary and basic steps for launching F1 help, whether with Help 2.x or Help Viewer 1.0.