Extend viewconf to support LOG_LEVEL_MAIN
##### "LOG_CONF_LEVEL_MAC": ____________________ == LOG_CONF_LEVEL_MAC
##### "LOG_CONF_LEVEL_FRAMER": _________________ == LOG_CONF_LEVEL_FRAMER
##### "LOG_CONF_LEVEL_6TOP": ___________________ == LOG_CONF_LEVEL_6TOP
+##### "LOG_CONF_LEVEL_MAIN": ___________________ == LOG_CONF_LEVEL_MAIN
