BY GEORGE O. SMITH ILLUSTRATED BY SMITH Someone behind me in the dark was toting a needle-ray. The impression came through so strong that I could almost read the filed-off serial number of the thing, but the guy himself I couldn't dig at all. I stopped to look back but the only sign of life I could see was the fast flick of taxicab lights as they crossed an intersection about a half mile back. I stepped into a doorway so that I could think and stay out of the line of fire at the same time. The i