Fix for WiFi networks secured with WEP

I just received my Spark Core yesterday, and when I went to configure its WiFi connection via serial I got the message about the Spark team having trouble connecting the CC3000 to WiFi networks secured with WEP. I ignored this warning and tried to connect anyway, only to find that it just got stuck on a flashing green light.

So I delved into the depths of the source code, and after a bit of research I found that wifi_add_profile_callback() in src/spark_wlan.cpp wasn't using wlan_add_profile() correctly. According to documentation I could find, WEP keys have to be formatted as byte arrays. I implemented something simple to parse the WEP keys when needed, compiled the firmware and flashed it onto my Spark Core, and after entering my WiFi network details it's now breathing cyan.

I created a github account just so I could share this fix in a pull request.
You can probably improve on what I've done; I'm just an amateur coder, so it's just a quick fix.