Using exceptions offers a better interface for the parser to
report errors.

It also makes more convenient to test the parser code.

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

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

- Add the remaining test cases for tiny containers.
- Add a new image type: tiny-lxc
- Add new execution type: all

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

Add the compatibility and performance test cases type to be recognized
by the parser.

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

Keep the test case data format private in the parser module.

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

This commit addes a parser for the test case format, so it can
detect the most common mistakes (missing field or incorrect types
for values) in the test case yaml file.

This commit also adds a few more ported test cases.

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