Introduce CFINCOMPATIBLE config parse result flag.
Sort interface rules by unsigned integer key.
Legacy and modern 'interfaces' config styles are now incompatible.
Validate config_network_interface struct to enforce that only exactly one of
'match' and 'dummy' options are set.
Add test cases for 'interface' config option.
Config Object Model parser now returns bitmask result of CFxxx flags and only
allocates root node if the config file is non-empty.
Added emalloc_zero().