Updates bow

Slight delay because yesterday some things took more time than I predicted..

But I think the tips presentation is ready now :). I added the git-prompt.sh file (which comes with a git install) to the repository just to be sure we have a backup in case the file is not available in the laptops.

Other than that, I skipped the autocrlf / safecrlf config since it seems more complicated for first-time git users. Instead, I added some slides about git add --patch for selective commits of line changes, which I think is more useful (and easier to grasp).

Anyway, comments are welcomed.