added default login/signup view controller

When app opens, it logs any current user out (workaround), then if no
one is logged in, opens the login/signup view controller. Signing up
adds a user (builtin) with name, email, and password.
added some more functionality to login/signup

Login screen goes away after you login. Signup only takes emails ending
in “hmc.edu”. Not clear how to display an alert for incorrect signup.
email validation

displays an alert as well if email doesn’t end with hmc.edu