Use claims principal all over the place.
- Changed jabbr to use custom claim to identify its id.
- Added ability to create an account from a claims principal.
- Change the meaning of IsAuthenticated throughout JabbR.
- Added the ability to create a user from a ClaimsPrincipal
Use normalized claim types for the jabbr id.
Create a new claims principal everytime if jabbr authenticated.
Make JabbR work with windows auth again.
- Normalize WindowsPrincipal in the AuthorizationHandler
  to have the claims jabbr requires to work.
- Changed the membership service to throw if required aren't there.