Refining the admin of the site on WordPress

Requires the completion of the site admin on WordPress. In the admin in the entry menu, remove unnecessary columns such as the author, tag headings, Category of the announcement and In the slider. It's necessary that the column with the record takes up the entire width of these columns. Specify in which file this code is most likely in function.php these lines comment and all I think so. If you can expand the column with another option, offer. 100 rubles in translation into poison, Webmani.