Use Dir[..] with sort to prevent different results

It seems that older Ruby versions (before openSUSE 13.2) have a different
order of the file list than newer ones. This shouldn't happen with sort.
Add meta data changes support to Factory

For some unit tests it was needed to influence the meta data
of the created descriptions.
Use CURRENT_FORMAT_VERSION as Factory format_version

There is no point in changing it manually during each format_version
upgrade.
Add additional factory options also to create_test_description_json
Make sure Factory created JSON looks like the machinery one

To make comparisons on JSON text level they formation needed
to be equal.
Replace static json data through Factory method

Use create_test_description instead of static json data wherever
possible to make it easier to adapt the tests after format
changes.
Use current format version where factory creation is not possible

Use the current format_version to not have to update it manually
all the time.