Update all repositories as part of start script

[commana]

From #14:

I think there is a need to automatically update all repositories that were created by Puppet. Normally, you would do this as part of your regular development workflow. But since we are using the machine for demonstration purposes, there should be some basic logic that keeps the repositories up to date.

I'm thinking of pulling in the changes if the repos are on the master branch, the merge is a fast-forward, and no local changes are present. For this I will create a separate issue and close this one.

The best way would be to include this in the start.sh script.