Revert "Added a login fragment- left the login activity, commented out a lot of things requiring you ot be logged in, attempted to get the internal login fragment working, but all it does is take in a username and pass and close the keyboard when the user hits log in.  but, when the user logs out, the app now logs you out, and returns you to the login screen, but you can still see all your cached data through the view cached data button.  this also still persists after closing the app."

This reverts commit 266c49433c66a6eb1fe1d7a380d42af02bc14d05.
removing gradebook, settings, and calendar