Revert "Removed stuff from ott."

This reverts commit 6ef2c1bfe043405f883f508156d29976ab77f56f.
Revert "Coq accepts the code as it is now. Cleanup is still needed."

This reverts commit b055cd5638ab30cf9460748e585070ab5eb9c742.
Revert "Started transition to pure Coq-code."

This reverts commit dd5bde6c856e28bb01825f01a2bdd7014cbe8e3b.