Lint

* Prefer g_ascii_strtoull to strtoull, g_snprintf to snprintf.
* Add glib/gprintf.h for g_snprintf.
* Remove unused stdio.h & stdlib.h includes.
* Add a couple of comments.
* Move parse_args to a more logical place in he file.

Change-Id: Ibda1a88391c4909f0fd055ef15099bfda316918c