Switches FacebookClient to use an array of scopes.
Improve Microsoft Client

Allow the developer to specify different scopes.  Set the default scope
to "wl.signin" instead of "wl.basic".  This provides a better
out-of-the-box experience.  See
http://stackoverflow.com/q/15125410/634824
Switches back default scope for MicrosoftClient.

We shouldn't change default values for a popular shipped class.
It would cause too many failures in existing web sites when they upgrade
that would be difficult to track down.
Merges improvements to MicrosoftClient.

Closes #256