emayili_emailer         Returns a function to send emails using the
                        'emayili' package.
is_logged_in            Display Shiny elements only if the user is
                        logged in.
is_not_logged_in        Display Shiny elements only if the user is not
                        logged in.
login_server            Login server module.
login_ui                Login UI elements.
logout_button           Logout button.
new_user_ui             UI for creating a new user account.
passwdInput             Password input textbox.
reset_password_ui       UI for resetting password.
use_login               JavaScript and CSS dependencies.
