How do you go about moving and restoring a six-story-high, 90-ton elephant? Very carefully. . . The Save Lucy Committee of Margate, N.J., has worked for over 15 years to preserve and restore this giant pachyderm. During this time they have battled odds that even the nearby Atlantic City casino owners wouldn't bet on, and they have turned doubters into elephant believers. In the meantime, they have become experts on the "care and feeding" of historic elephants. Surprisingly, Lucy the Elephant is not one-of-a-kind. At one time there were three giant elephants built in the U.S. The Light-of-Asia elephant was a 40-foot wooden beast in South Cape May, N.J.; she was demolished and the "remains cremated" in 1900. Lucy's other cousin