This adds a wlan.config(reconnects=N) option to set the number of reconnect
attempts that will be made if the WLAN connection goes down. The default
is N=-1 (infinite retries, current behavior). Setting
wlan.config(reconnects=0) will disable the reconnect attempts.
A nice side effect of reconnects=0 is that wlan.status() will report the
disconnect reason now. See related issue #5326.