Update lsl/OpenCollar - listener.lsl

tandem with auth script for issue # 1454

removed always-set-autoprefix & replaced with settings request in case of individual reset && re-enabled + touched up the reponse-empty segment to set prefix to autoprefix in the event of no settings entry
added notify-sender for messages that auth used to handle (it'll send using LM_SETTINGS_RESPONSE)

changed "sChan" integer variable name in listener section to "iChan" just because it was driving the ocd portion of me nutz