Homo Sapiens, the Manna Maker

F M Esfandiary article on threshhold of age of limitless abundance of energy, food and raw materials; describes new sources of energy, new methods of food production and new accessibility of limitless raw materials; cites as 'short-sighted' exhortations to no-growth at time when world needs more growth not within but beyond industrialism; says people around world face scarcity not because of lack of resources but because of billions of dollars squandered on armaments; sketch (M)