Added a 1-bit flag 'large_scale_tile'. If it is 0 that is the default value,
use normal tile coding in TILE_GROUPS. If it is 1, use large-scale tile
coding in EXT_TILE.

At large_scale_tile=1 case, if single-tile-decoding is required, then the
loopfilter is disabled.

Related API and unit tests were modified.

Change-Id: I3ba12dc3d80ccf1ab21543ab3b16c02282c34e3b