GREEN POLITICS: THE GLOBAL PROMISE, 2nd ed. by Charlene Spretnak and Fritjof Capra New York: E. P. Dutton, 1986; 224 pp., $12.95 SEEING GREEN: THE POLITICS OF ECOLOGY EXPLAINED by Jonathan Porritt Oxford: Basil Blackwell, 1985; 249 pp., $24.95, $6.95 paper THE SPIRITUAL DIMENSION OF GREEN POLITICS by Charlene Spretnak Santa Fe, N.M.: Bear & Co., 1986; 95 pp., $4.95 paper