dca: Convert dca_dmixtable to integers

Also include zero in the table, eliminating a special case in the
decoder.

Signed-off-by: Niels Möller <nisse@southpole.se>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
avcodec: bump version after rotation api

Signed-off-by: Kostya Shishkov <kostya.shishkov@gmail.com>