Devise authentication

added devise authentication (more secure, admin has ability to login/logout, more than 1 admin with different passwords possible), removed http basic auth, options in config.yml to control how admin logs in + whether registration possible

NOTE -- to get password reset mailer working, each user must follow http://ridingrails.net/devise-authentication-recover-password-email-code-kata/ (very easy)...or can just disable the password reset option/links/be okay with the links being there but not sending emails