Selected Ion Flow Tube Study of the Gas-Phase Reactions of CF\\r sup+sup\\r , CF\\r sub/2subsup+sup\\r , CF\\r sub/3subsup+sup\\r , and C\\r sub/2sub\\r F\\r sub/4subsup+sup\\r with C\\r sub/2sub\\r H\\r sub/4sub\\r , C\\r sub/2sub\\r H\\r sub/3sub\\r F, CH\\r sub/2sub\\r CF\\r sub/2sub\\r , and C\\r sub/2sub\\r HF\\r sub/3sub