Hackish way to quickly make sure slapgrid-ur is correctly ran 1/ once a day, randomly during the day, 2/ without error

slapos-start exit with 0 if no slapos.cfg is found

	 - Check if all parameters are in section 'slapos' and 'slapformat'
	 - Detect duplicated lines in cron.d
	 - Added comments

Slapprepare now propose default parameters