Changing type of od_state.bsize to unsigned char.
Fixes desync created by level-2 motion vectors.

The mv grid is iterated over the number of blocks but the vectors
 are on the corners so we need to go one further. This mattered
 because the encoder was choosing to use some level-2 vectors whos
 supporting vectors were on the right edge of the image.
Adding support for lapping with mixed block sizes.
PVQ encoder doc: model combination
Better MV coding.

Uses the Laplace coder instead of uniform probabilities.
Original patch by Gregory Maxwell.
Switch encoder and decoder into superblock hierarchical order.

This cause a minor PSNR loss due to the UR predictors being temporarily
 disabled.
Disable image dumping when !OD_DUMP_IMAGES.
Adding Mathematica notebooks with the pre/post-filter computations.