Created by: ycho

• Add update_partition_context() function.

• Add partition_context_lookup[] and subsize_lookup[] tables.

• Add mi_size_wide[] and mi_size_high[] tables.

• Fix outdated lookup tables, for ex: all 2x2, 4x2, 2x4 are dropped.

• Use BLOCK_SIZES_ALL whenever possible for the size of lookup table.

• As a separate commit for submodule libaom, manually update the corresponding lookup tables, esp. all the tables with the size BLOCK_SIZES_ALL.