Combine crumbs, sugar and margarine; press onto bottom of 23 cm springform pan. Bake at 160ºC ., 10 minutes. Cool. Soften gelatin in water, stir over low heat until dissolved. Add juice, egg yolks, quarter c sugar and peel; cook, stirring constantly, over medium heat 5 minutes. Cool. Gradually add gelatin mixture to the softened Light Neufchatel cheese, mixing at medium speed on electric mixer, until well blended. Stir in a few drops of green food coloring, if desired. Beat egg whites until foamy; gradually add remaining sugar, beating until stiff peaks form Fold egg whites and whipped topping into neufchatel cheese mixture, pour over crust. Chill until firm. Garnish with additional lime peel, if desired.