Add tests for local color tables in gif parser.
Skip image blocks in parser.
Set transIndex for GIFs with transparent pixels.

Fixes #201.
Decode GIFs with more codes than can fit in table.

Fixes #203
Avoid drawing recycled Bitmaps in GifDrawable.

Fixes #202.
Add fullscreen activity to GIF sample.
Reset frame pointer in setData in GifDecoder.

Fixes #204.