cabac: remove leftovers from the cabac encoder

The cabac encoder was only used by the removed cabac test.

Signed-off-by: Janne Grunau <janne-libav@jannau.net>
aarch64: configure: set arch dependent features

Stack is always 16 byte aligned and clz, 64bit operations and unaligned
memory access are fast in aarch64 mode on ARMv8.

Signed-off-by: Janne Grunau <janne-libav@jannau.net>
aarch64: bswap inline assembly

Signed-off-by: Janne Grunau <janne-libav@jannau.net>