Implemented some options descriptions up to get_config_file_options.
Added new options descriptions for get_web_options and get_network_options.
Implemented new options descriptions up to get_help_options.
Implemented new version of get_rethinkdb_create_options and get_rethinkdb_serve_options.
Implemented new version of get_rethinkdb_proxy_options.
Implemented the new version of get_rethinkdb_admin_options.
Implemented the new get_rethinkdb_import_options.
Implemented the new get_rethinkdb_porcelain_options.
Implemented parse_commands and parse_commands_deep but not parse_config_file_flat.
Made main_rethinkdb_create use the new kind of options (which unfortunately are broken with respect to default values.
Made parse_command_line insert default values into the map.