Fix indent, whitespaces and a close a couple of unbalanced tags
Fix whitespaces and indent
Add hybrid and disabled outbound NAT, fixes #2416:

- Add 2 new outbound NAT modes, hybrid and disabled, manual and advanced
  keep working the same way
- Hybrid mode applies manual rules first, automatic after
- Disabled do no create any outbound NAT rules
- Remove ipsecpassthru config field and rename advancedoutbound to
  outbound
- Save mode on $config['nat']['outbound']['mode'] to simplify the logic
- Modify config.default to reflect changes
- Add code to upgrade config, and change latest_version to 10.3
- Use html to align modes and remove some hacks to align using &nbsp;