First integration tests trials

* Use of pexpect
* Wrap to ensure that we don't spawn any uncontrolled errors or warnings
* Tests for installing, reinstalling, some default handlings and detection
  if installed (more to come)
Minor cleanup
Add a new launcher_path method change launcher add

* get_launcher_path new method + add tests
* using that one in other spaces
* launcher is now added before the running apps if any, or at the end if
  not present