Not all GIFs start with a clear code

[MarkJeronimus]

While debugging some gifs that even Paint Shop Pro fails to render (but Windows, Firefox and Microsoft GIF Animator do read correctly) I found all of them had no clear code as the first code in each frame.

Removing line 202 fixed it.

bits.read(); // Skip leading clear code

However this breaks all other GIFs because now their clear code is interpreted as a color code. Need to investigate.

[MarkJeronimus]

Some NSFW gifs without clear code:
https://chan.sankakucomplex.com/post/show/227707
https://chan.sankakucomplex.com/post/show/249327
https://chan.sankakucomplex.com/post/show/280646

[MarkJeronimus]

It may be a band-aid, but this fixed it for me:

GifDecoder.java:201

		codes.clear(); // Init code table
		int code = bits.read(); // Read first code
		if (code == clearCode) { // Skip leading clear code
			code = bits.read();
		}
		int[] pixels = tbl[code]; // Output pixel for first code