Added notification for animals which haven't sent positions in a long time

The max accepted number of hours w/o positions is
configured in the ini file.
Notifications are sent to both the owner and the
admin users.
Also made some additional refactorings and added
some utility methods.
Send non-communicating device notifications by steps

Now we can configure through the ini files how many
positive checks onto an animal not sending posi-
tions it will take to send each type of notification
(web, mail, sms). SMS's are not sent to the admin
users right now, only to the owner.