[BUGFIX] add column at right place

* Improved handling of last column
* Improved handling of setting CSS
* Removed unnecessary reference to addColumn

__Tasks:__
- [ ] gather feedback for my changes

__Informations:__

| Q             | A
| ------------- | ---
| Fixed tickets | #345 
| BC Breaks     | none
| Doc           | none
@danrot please use the dom.createElement method