Add day offset methods to the Clock entity.

Signed-off-by: Max Fierke <max@maxfierke.com>
Add Mailer for notifying employees and their supervisors when they are late.

Signed-off-by: Max Fierke <max@maxfierke.com>
Add late clock-in checking console command.

Add's clock:check-late to the OpenSkedge console.
Implements issue #23

Signed-off-by: Max Fierke <max@maxfierke.com>