Edit's to make demo work on ARM architecture reliably

[H4LL]

Previously the demo in /scriptswould fail when I tried to run it on ARM architecture. I made some edits to specify platform so that the docker environment knows to use virtualised hardware as no implmentation exits on native ARM. If it's of use to anyone I'd be happy to make a PR. Here's my branch for reference: https://github.com/H4LL/traction/tree/arm_virtualisation.

Thanks for creating traction. It's an awesome tool. I'm loving it so far!

[swcurran]

Awesome and much appreciated if you could put in a PR. Thanks!