Refactor command parsing

- normalize command line before parsing
- compare whole words
- check for missing/extra arguments in config parsing
- use strdup for string allocation
- share code for reporting syntax errors
- avoid using function pointers
- cleanup the code a bit

main.c

@@ -284,7 +284,7 @@ go_daemon(void)
 int main
 (int argc, char **argv)
 {
-  char *conf_file = NULL;
+  const char *conf_file = DEFAULT_CONF_FILE;
   char *user = NULL;
   int debug = 0, nofork = 0;
   int do_init_rtc = 0, restarted = 0;