hevc: simplify SAO computation, delay from one row its computation
hevc: move restore_tqb where it should be.
hevc: use local variable for split_cu_flag
hevc: separate residu and prediction (needed for Range Extension)
hevc/rext: basic infrastructure for supporting range extension
- support for 4:2:2 and 4:4:4 up to 12 bits
- add a new profile for range extension
hevc/rext: add support for Range extension tools

SPS features/flags:
- transform_skip_rotation_enabled_flag
- transform_skip_context_enabled_flag
- implicit_rdpcm_enabled_flag
- explicit_rdpcm_enabled_flag
- intra_smoothing_disabled_flag
- persistent_rice_adaptation_enabled_flag

PPS features/flags:
- log2_max_transform_skip_block_size
- cross_component_prediction_enabled_flag
- chroma_qp_offset_list_enabled_flag
- diff_cu_chroma_qp_offset_depth
- chroma_qp_offset_list_len_minus1
- cb_qp_offset_list
- cr_qp_offset_list
- log2_sao_offset_scale_luma
- log2_sao_offset_scale_chroma