Generate new tests files with the recent format changes.

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

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 adds the unit test module for the renderer.

It includes tests for the parser, renderer and relevant formatting
methods. It also adds a set of files that are used by some of these
tests.

The commit also updates the README file explaining how to execute
these tests.

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