add sx50 beta to autobuild, remove a1200 beta label - from waterwingz in http://chdk.setepontos.com/index.php?topic=650.msg98806#msg98806
add a1100 100b as a copy of 100c, a2200 100c as a copy of 100b - from nafraf in http://chdk.setepontos.com/index.php?topic=650.msg98809#msg98809