Unified API for authentication (KornellSession)
getCurrentUser(Callback<UserInfoTO>) //Async 
getCurrentUser() //Sync - May throw NPE
Merge branch 'master' of https://github.com/Craftware/Kornell

Conflicts:
	kornell-gwt/src/main/java/kornell/gui/client/presentation/bar/generic/GenericActivityBarView.java
	kornell-gwt/src/main/java/kornell/gui/client/presentation/course/ClassroomPresenter.java
	kornell-gwt/src/main/java/kornell/gui/client/sequence/PrefetchSequencer.java