Feature/write through cache perf

-> Adds in a caliper project, and a benchmark

-> Add in a HHFiltered store, we use a local mutable CMS sketch to keep track of heavy hitters, only storing those in the cache. Yields drop in read I/O by 30%
there is a difference in this change. Here you are hitting the clock even when the item is absent. Originally, we only check the clock if the item is present. This will make cases of high miss rate more expensive. Can you keep it in the closure, but just make it more verbose there, like add a comment?