Allow re-use of column specifications across templates

[jpfeuffer]

It would be great if one wouldn't need to specify the same column over and over again across many templates.
Therefore I think it would be better if columns were single modular components.

[ypriverol]

You mean a column should be in one and only one template?

[jpfeuffer]

No, I think ideally columns should be separate from templates and only included/referenced in them.