The parameter aid followed -a is aid of the connected station. If aid is 0, kick out all of the connected stations.
2. Add block parameter to api esp_wifi_scan_start.
If block is true, the api blocks before scan done or returns directly.
2. Add struct station_list into tcpip_adapter layer
3. When ap -L cmd is received, get mac address from mac layer first and then search ip address based on mac address on dhcp layer.
