In this assignment you will create a "login" system.
Due 9/21 by demo.

Note: passwords must be hashed and salted!

1. The first activity should have two edit text boxes. One for a name
and one for a password. Consider using inputType="textPassword" on
the password edit text box.

2. The first activity should have a login button. The login button
will check the name in the name box and the password in the password
box to see if there is a match in a sharedpreferences file. Use the
name as the key and the password as the value in the sharedpreferences
file. If the name is not in the sharedpreferences file, then the login
has failed. Handle this appropriately. If the name is in the file,
then the passwords must match. If they do not, then the login has
failed. Handle this appropriately. If the name and password match when
the user presses the login button, record the user's name as the
currently logged in user (in sharedpreferences, perhaps in a new file)
and open a new activity.

3. The first activity should have a register button. As long as the
name does not exist in the sharedpreferences file, then the register
button will create a new name/password pair in the sharedpreferences
area. If the name did exist, then registration fails. Handle this
appropriately. If the registration is successful, then record the
user's name as the currently logged in user (in sharedpreferences,
perhaps in a new file, but the same as the end of the login process)
and open a new activity.

4. When a login or registration succeeds, a new activity should be
loaded. The new activity should look up who is logged in currently
(via login or register) and display the name to the screen.


General Note: You must hash and salt your passwords for storage for
full credit. You can read more on the website about how to make this
happen. Storing any personal information in shared preferences without
some sort of encryption is a bad idea. All of this information is
"easily" available to anyone accessing the phone. The main 394 page
has a discussion about both encryption and hashing.