- README improvements:
  * Add link to external source code
  * Add link to application README
  * Explain how to stop the AMI
  * Various clarifications
- CLI improvement: Add a centralized ats.sh script that is used to
bootstrap, build and run.
- Fix warnings
- Fix Keil MDK project.

Signed-off-by: Vincent Coubard <vincent.coubard@arm.com>