Return to merge scan width of 16

This was reduced before the use of binary blocks was committed

src/leveled_sst.erl

@@ -72,7 +72,7 @@
 -define(COMPRESSION_LEVEL, 1).
 -define(BINARY_SETTINGS, [{compressed, ?COMPRESSION_LEVEL}]).
 % -define(LEVEL_BLOOM_BITS, [{0, 8}, {1, 10}, {2, 8}, {default, 6}]).
--define(MERGE_SCANWIDTH, 8).
+-define(MERGE_SCANWIDTH, 16).
 -define(DISCARD_EXT, ".discarded").
 -define(DELETE_TIMEOUT, 10000).
 -define(TREE_TYPE, idxt).