Hybrid 1-D/2-D transform coding

This commit enables a hybrid 1-D/2-D transform coding scheme and
the accompany entropy coding system. It currently uses hybrid
1-D/2-D DCT transform coding. It provides coding performance gains:

lowres_all  0.55%
hdres_all   0.43%

Change-Id: I2b30dcafd21eb2bb3371f6e854cbab440a4dfa78
8 files changed