Avoid crash during wifi scan due to reading invalid RAM

[monkbroc]

Update WICED so that marginal scans of WPA protected networks don't lead to a crash.

Fixes #651

@m-mcgowan do you prefer rebuilding WICED yourself? This is the only library that changed, but the other ones rebuilt with a few bytes different (different compiler version, build date and paths probably).

[m-mcgowan]

Hey @monkbroc! While surveying the code, I noticed we don't yet have any tests in wiring/no_fixture for WiFi.scan(). Please add a generic test that simply runs WiFi.scan() as a smoke test. (If the returned values can be validated, such as valid SSID name/length, BSSID etc.. that is nice, but not essential.) Let @sergeuz know when this is done so he can independently compile and run the tests.

[monkbroc]

I added a WiFi.scan() smoke test. It just checks if there is 1 or more AP found. I can't think of a better validation.

@sergeuz could you please compile this branch and run the wiring/no_fixture tests?

[sergeuz]

@monkbroc The test works for me