This commit applies several changes in order to turn the
renderer code into a proper python module and command that
can be easily installed using the setuptools module.

Main changes:
- Main executable is named atc
- Use setuptools to install renderer executable
- Improve tests so they can be easily executed by packages
- Update README instructions

Signed-off-by: Luis Araujo <luis.araujo@collabora.co.uk>

This commit also adds a new macro 'macro_modules_preconditions'
to make convenient adding the preconditions for the library modules
test cases.

Signed-off-by: Luis Araujo <luis.araujo@collabora.co.uk>

- Adds a command line interface to the renderer to process a single
  test case yaml file or a directory of files.
- Adds the feature to write the test case html page inside a specific
  directory.
- Port few more test cases to the yaml format.

Signed-off-by: Luis Araujo <luis.araujo@collabora.co.uk>

- Add a new post-condition section.
- Add a new macro to install packages for automated tests.
- Slightly change the way the function to parse lists work. Now
  only the run.steps section will be treated different from
  other sections.
- Apply syntax changes to the already ported test cases.
- Add new ported test cases.
- Update the README explaining a rule for the formatter.

Signed-off-by: Luis Araujo <luis.araujo@collabora.co.uk>

This commit updates the remaining test cases with the supported
format.

It also adds a first macro to conveniently add common pre-conditions
for ostree test cases.

Signed-off-by: Luis Araujo <luis.araujo@collabora.co.uk>