setSecurity not working as expected

Hi, I've just looked into this, and I found that there was an issue inside the Bluetooth stack where sometimes the keys used for secure pairing weren't aligned on word boundaries.

Unfortunately it looks like the Puck.js 2v04 build was one of those builds - passkey pairing would have failed and you should have been unable to access characteristic AB41. If you try a cutting edge build from http://www.espruino.com/binaries/travis/master/ then it should now be fine.

However while at that point Android will request a passkey if you connect using the OS's menu, if you go through NRF Connect it won't. It will only require the passkey either when you explicitly try to bond, or when you try to access the 0xAB41 characteristic that you specified security for. I'll update the docs to reflect that.