(trust not a grantor trust where it contained a "distribution committee" that barred grantor from retaining sufficient powers to cause trust to be treated as grantor trust under I.R.C. Sec. 677; it might be possible that sufficient power to cause trust to be treated as grantor trust existed under I.R.C. Sec. 675, but determination only possible after returns filed; trust contributions not completed gifts until time of distribution from trust).