A small house keeping release in part to get ready for Windows Template Studio work.

Included are the following:

• #443 Remove a rogue dependency on System.Web that was accidentally included.
• #462 WPF Window Manager won't override a Window's Title if it's been set. Thanks @tziemek.
• #466 Add a Set implementation to `PropertyChangedBase.
• #475 Platform provider methods are now virtual.