Remove circular import
Remove circular import

helios.security imports models so you got a NameError when
importing helios.models in server_ui/views.
So, moving helios.models.Election to home function scope.
Also, removing unused imports

shirlei/helios-server,shirlei/helios-server,shirlei/helios-server,shirlei/helios-server,shirlei/helios-server