MB-29243: Add --json option to mctimings to print JSON
MB-29243: Add --json option to mctimings to print JSON

JSON output is easier to parse than the histogram

Change-Id: Id3c1d13486987c2484f21df3f7f2f9b817b67732
Reviewed-on: http://review.couchbase.org/92704
Tested-by: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Jim Walker <1cd02e31b43620d7c664e038ca42a060d61727b9@couchbase.com>

daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine