Default jails to use same network as host

- Modified sipcalc class to take interface as well as network keywords.
  This allows passing an interface to sipcalc so that the proper network
  configuration can be determined

- Added method to notifier to guess the primary interface on the host

- NAT is off by default

- Logic added to jail form that determines if jail being configured is
  on a private network or the host network and handles accordingly

- When saving the jails configuration, save with the proper netmask or
  prefix length

- New fields added to the jails configuration model

- The jails configuration attempts to determine the primary network of
  the host machine and sets it as the default

- Update progress meter to have initial guess time of 10 minutes