Self-updating code

In what is probably a very bad idea, I've decided to have a crack at writing some code for the Espruino which will update itself. i.e, you flash a bootstrapper to the Espruino, and after it runs its first init, it will fetch more javascript code from the internet (even the bootstrapper code), write it to the node_modules folder on the connected SD card, and reboot into the new code.

Basic tests have gone well, but no doubt I will run into some critical issue at some point.

As for why, I need to be able to deploy my Espruino WiFis to a location and not require them to come back to me to be updated, so self updating is a must.