- Raise early
- Also add sanity checks and correct output errors.
- This was outputting bad error message in some cases, making debugging
impossible.

- Clearly define the imports
- Refactor specific mockup

Fix additional_buildout_parametr_list to read
additional_buildout_parameter_list

Conflicts:
	slapos/format.py

  Now configurator and accurate dependence chain handle the list of
  business templates to install.

 Those business template should be installed automatically