Model rework

Reworks the userModel and sessionModel Dummy to have alerts treated more property like.
So instead of:
  self.session.pushAlert()
it becomes:
  self.session.alerts = self.session.HTMLAlert()

Which I think is a little more understanding of whats happening, since most often you only have one alert, and this way you have greater control over how the alerts are created and styled. so long as you do this:
  self.session.alerts = {"expire": "next", "alert": "This is an alert"}
You're good to go. HTMLAlert() does this and works just like pushAlert.

pushAlert has been kept in for compatibility with older code, but I may refactor it later on.