rc.local service expects ap@wlan0 and wlan0

[tmack8001]

Some configurations may not have successfully created both AP and wlan0 (say RPi 2 Model B with a wireless adapter that doesn't support a combination of interface modes).

Not a huge issue, but our default image configuration should only try to turn off power management if and only if the interface is successfully created.

Likely we should track and display the wireless/network interfaces that are available on the /about experience and separating the dependencies between our flask+python service and networking interfaces.