Supports HM9.2 bitstream

updated cabac sao_type_idx initialization
updated cabac split_transform_flag initialization
updated VPS parsing
moved vps_temporal_id_nesting_flag
minor white space fixes for get_bits calls
hevc: cabac: replace custom engine by cabac.c
hevc: cabac: don't compute ctx_idx_offset explicitely
hevc: cabac: simplify and optimize
hevc: cabac: optimize initial state computation

This is the same optimization than in h264_cabac.c