pfSense

Fix undefined and unused variable warnings in interfaces.inc

Notes: * interfaces_tunnel_configure() * loop continue on address type "track6" never hit, defined variable is
'$ipaddrv6' but was referred to as '$ipaddr6' * interface_bring_down() * '$old_router' was populated with the contents of a file but never used...

Replace direct config array accesses in interfaces.inc

Replace some direct config array accesses in wizard.php

Correct deprecated implode() syntax

Fix warnings in guiconfig.inc, unexpanded string in get_config_path call

Replace config array accesses in guiconfig.inc

Change some config array accesses in interfaces.php

Replace some config array access in services_dnsmasq.inc

Replace config array accesses in create_interface_list()

Fix multilevel array access outside config in util.inc

• Add generic array get/set path and path_exists functions to util.inc
• Wrap these more generic versions with the confg_* equivalents