Update: Improve example bootstrap script, exiting properly on error.

Update: Improve example bootstrap script, exiting properly on error.

The `bootstrap-example.sh` has been used as a demonstratable example that can be used to build this project.
This script has become incredibly convenient but I had not made it as resilient as it could be.

This changes the script to properly exit with a non-zero return code on error.
This should allow for adding this script to a series of bash commands along with the conditional operators like `&&` and `||`.