firmware download script:
 * do not download powerline-, wlan-repeater-, and VoIP-gateway-firmwares, these are not supported by freetz
 * labor/beta: consider ftp://service.avm.de/Beta/ while downloading labor/beta firmwares
 * stable: consider ftp://service.avm.de/Downgrade/ while downloading stable firmwares


git-svn-id: file:///var/svn/freetz/trunk@11826 149334a1-2f27-0410-a3b9-fc62619ac1e6