- updated to 2.0.28, removed obsolete gif patch

- updated to 2.0.28, removed obsolete gif patch
- GIF support is back in upstream sources
  gdImageOpenPolygon(), gdImageCreateFromGifSource(), gdImageLzw*,
  gdImageBigGif*, gdImageGifToSink() functions
  and gd2togif, giftogd2, gdcmpgif progs have been dropped
  (fortunately doesn't seem to be used in current php, perl-GD or anything now)
- removed gif,lzw bconds, always provide gd*(gif)

Changed files:
    gd.spec -> 1.100