This test is a stand-alone program that tests performance for writing
and reading ot a dummy rocksdb database. It also is a good way to see
just how much memory rocksdb uses during normal operation.
I modified this test a little bit to use multiple threads when reading
and also I cleaned up the code a little bit.
I have been using this/will use this to evaluate options that reduce
memory consumption.
Also added a blurb/description to the quick-config regarding
db_max_open_files.
