CID 1260 (as evidenced by incorrect decoding of a sample from ticket
4876) seems to use incorrect weight tables. It appears those tables
were not zigzag-scanned.

Apply zigzag on weight tables for new CIDs 1258, 1259, and 1260, and
fix an incorrect chroma table for CID 1256.

Fixes last issue from ticket #4876.
Found-by: Christophe Gisquet <christophe.gisquet@gmail.com>
Signed-off-by: Christophe Gisquet <christophe.gisquet@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>