Match `DecodeSS2`

[disinvite]

For once, the question of what this should do is answered easily: https://github.com/thinkbeforecoding/nomemalloc.handson/blob/master/flic.txt

I have these variables worked out from the beta if it helps. Beyond that, the code is a mess.

short xofs = 0;
short yofs = 0;

short width = (short) p_flcHeader->width;
short token = 0;

short xmax = xofs + width - 1;

short row = yofs + p_flcHeader->height - 1;
short* data = (short*) p_data;

// The first word in the data following the chunk header contains the number of lines in the chunk.
// The line count does not include skipped lines.
short lines = *data++;