Added login functionality

-may have deleted somethings based on commit comments, but they may not have been mine. Be sure to double check.

Main Login activity will now denied access to main activity if you do not create a user and password on the registration page. Login user, and password as remember from run to run. -Some security flaws likely still remain

-created a singleton object for later use and testing (maybe be abandoned)

-added serializable to to some data classes, and completed some of their functionality -ie. change, get, etc -data classes are still incomplete

-current data classes are not likely to be the final ones to be sent to server