Stashing Katana Auth work
Started a new authentication service to pull auth-related stuff out of UserService.

Also, as a demonstration of a cleaner service layer.
Implemented AuthenticationService.AuthenticateUser
Stashing auth rearch
Moved things over to use UserSession instead of IPrincipal
Moved authentication logic to its own service
Fixed up infrastructure
Switched to default auth cookie name
C is for COOKIE AUTH!
Fix issue with IStatisticsService bindings being null
Added a glimpse tab to view auth info.
Added API Key auth middleware
Updated ApiKey Auth module to be path-specific
Configured cookie and API key auth to play nicely
Got it building with the new GetCurrentUser() helper
Most unit tests passing
Updated Facts.
Added middleware to force ssl when authenticated
Updated to NuGet.Core 2.7.0.1 to resolve conflicts with dev
Merge branch 'anurse/1659-owinsecurity' into dev

Conflicts:
	tests/NuGetGallery.Facts/packages.config