Condemnation proceeding filed under Article 9 of Chapter 136 to take defendant's leasehold interest in property for highway improvement purposes; whether, because defendant had a nonconforming billboard on the property under a long-term lease, the value of the property interest taken from defendant should have been determined under N.C.G.S. 136-131, defining 'just compensation' for a condemnation proceeding under the Outdoor Advertising Control Act, rather than under Article 9, governing DOT condemnation actions in general; whether certain evidence is admissible to help the trier of fact determine the fair market value of the condemned leasehold.