Unify versioning policy across application

[ivanperez-keera]

Different versioning policies were applied to this project during history. From Major.Minor.Status.Iteration to Major.Major.Minor.Iteration.

It should be unified again.

The following files are affected by the policy and need to be adapted with every version bump:
keera-posture.cabal
src/Controller.hs
src/Model/Model.hs
po/es.po
po/gl.po

Also, the repo needs to be tagged with every release, changes documented in the changelog, and a tar.gz uploaded to hackage.

[ivanperez-keera]

https://stackoverflow.com/questions/2892586/how-can-my-haskell-program-or-library-find-its-version-number