Cream Cheese Lemon Bars . Oh man I love lemon.    -		 1 box lemon cake mix  -		 1/3 cup butter or margarine - softened  -		 1 egg  -		 8 ounces cream cheese - softened  -		 1 cup powdered sugar  -		 1/2 lemon - grated  -		 2 tablespoons lemon juice or 1/2 fresh squeezed lemon  -		 2 eggs  -		 1 teaspoon vanilla