Added unit test sheiit | Added TileInfo functions

TileInfo.setFGSpriteID(tile, id)
TileInfo.setDensity(tile, flag)
TileInfo.setBGSpriteID(tile, id)
TileInfo.setMetaData(tile, metadata)

TileInfo.isDense(tile)
TileInfo.getFGSpriteID(tile)
TileInfo.getBGSpriteID(tile)
TileInfo.getMetaData(tile)