changed lower_limit according to updated Poloniex limits
changed lower_limit according to updated Poloniex limits

BitBotFactory/poloniexlendingbot,Mikadily/poloniexlendingbot,Mikadily/poloniexlendingbot,BitBotFactory/poloniexlendingbot,BitBotFactory/poloniexlendingbot,BitBotFactory/poloniexlendingbot,Mikadily/poloniexlendingbot