CHICAGO (Reuters) - A consumer group wants to keep Tony the Tiger from promoting sugary cereals on the SpongeBob SquarePants cartoon show or anywhere else kids are watching. The Center for Science in the Public Interest said on Wednesday it would sue Kellogg Co., the maker of cereals such as Frosted Flakes, and Viacom Inc., which runs the Nickelodeon cable network, if the companies do not change some marketing practices aimed at children. The Center said letters had been sent to Kellogg and Viacom saying it would settle for a commitment from the companies within 30 days rather than sue....