Create tests for CLI

[KaiVolland]

Currently there are no tests for the functionality of the geostyler-cli.

It would be nice if we can find a way to test:

• all the option parameters
• expected structure of nested files and folders
• behaviour of mixed files in a folder (e.g. folder includes *.txt. *.jpg files)

IMHO the content of the created files should not be tested as this is in the responsibility of the parsers themselves.

Maybe @marcjansen has an idea of how we could test this as this is outside of the JS scope and I have not much experience on testing things on the filesystem base.

[geographika]

Several of the above are covered in the new test script in #343

[KaiVolland]

I close this as @geographika thankfully added tests some time ago.