Feature: Improve user authentication

[brianwarner]

Authentication is quite basic at this point, mainly intended to allow you to show someone else the results without them changing the configurations or accidentally deleting important things. Facade simply uses PHP sessions to determine if someone is logged in or not. There's no way to stay logged in, for example. Also, there may be much more secure ways to do this that I'm not aware of.

I would welcome input from someone smarter than me on how to improve the robustness of user authentication.