Fix errors introduced with merge 4dd435e7e5b6f82bd776b7b07b1de62cbd1bdf11

Merge 4dd435e7e5b6f82bd776b7b07b1de62cbd1bdf11 (PR #39) fixed the same problem as PR #42, and was merged after #42. As a result, the config file got broken, probably due to a bad conflict resolution.

Also, as an side effect, the specs to test for a valid config file got deleted too.

This patch reverts those commits and restores the config file structure.