Upgrade configuration schema macros to allow optional "default label"
argument to SUB_STRUCT and VALUE_SUB_STRUCT elements.
New STRUCT_DEFAULT section declares alternative STRUCT default values
with a label.
Remove array key SORTED flag; all arrays are now sorted by key
Use representation's comparison function for sorting arrays, not
a schema-supplied comparison function.
All STRUCT cf_fmt_config_xxx() functions omit invalid values, silently
if the invalid value is the default, otherwise with a non-CFOK return
value.
The "config dump --full" option includes all options with valid values,
otherwise omits options having default values.
Replace 'parsefunc' (cf_opt_foo) function arguments in schema
declarations with 'repr' (foo) names, which are used to declare
cf_opt_foo and cf_fmt_foo.
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.
Change a test case: configuration options are now case sensitive.
Fix config file load and parse logic in conf.c, always copy 'debug' flags
from config.debug.
The config schema 'interfaces' option is no longer MANDATORY.
Introduce new CLIFLAG_PERMISSIVE_CONFIG to supress bad-config ERROR messages
from the 'config set' and 'config get' commands.
Refactor cli_execute() into cli_parse() and cli_invoke(). Use *const* struct
command_line_option everywhere.
