(Ch. 12 debtor objected to creditor claim under farm equipment lease; debtor asserted lease was disguised as purchase agreement and security agreement which was not entitled to preferential treatment as lease; agreement provided debtor would make monthly payments for use of equipment with option to purchase at end of term at 10% fair market value at outset of lease; court held agreement constituted secured transaction under Neb. Rev. Stat. §1-203 and was not a lease; amount to purchase equipment at end of term was nominal, because only economically sensible decision was for debtor to exercise purchase option).