[NTG-context] minimals: I'm not guilty :)

Hello, I have applied the changes to mtx-update.lua made by Hans without really testing them:

hm, just copy to mtx-update

it forces us to fix things

Now you need to use --force to really do anything useful (you might need to update first-setup.sh/bat; I would prefer it without --force, but well ...). If anything is really broken, there is still "update-old". Mojca