Add "Column" to feature types in CMS

[kissane]

Now that we're on our own servers, I think we can do this at last, yes? :)

[ryanpitts]

@kissane Actually you can do this right from the admin! Open up "Sections" from the Article admin area, and "Add Section" at upper right. Give it a name like "Columns," and then add a subcategory like, say, "Column"?

Once you do that, the new option will show up on the dropdown for any article. And the Section name is what shows up in the flag to the left of article headlines in the new design.

We aren't making use of Category in the new design (although for it to show up in the Article admin dropdown, a Section still must have at least one Category). We can discuss ripping that out if you like, or keep it around for metadata purposes.

[kissane]

Actual tears.