Use concerns instead of mixins
Restore previous version because this doesn't work
Refactor cell

Change mixins for concerns. Decrease function complexities. Use undoable
functions.
Update cells to comply with refactoring cell
Fix non enumerable values to be undefined
Fix action empty calls
Merge branch 'feature/sig/refactor' into develop
Merge branch 'develop' of https://github.com/Derkje-J/programming-life into develop