Catalogue reorganization

Since our unmoderated catalogue became almost unusable, we decided to reorganize it.

Publishers won't be able to select categories for their ad units any more.

Most of the existing ad units will be moved to category "Unknown". New ad units will appear in this category automatically.

We will manually assign other categories to ad units we like. And we will try to optimize the tree of categories.

Catalogue reorganization will be ongoing process. It should improve advertisers' experience as well as income of our best publishers.