refs #5592 move circular_buffer, omt, threadpool, growable_array, rwlock, frwlock, kibbutz, mempool, partitioned_counter, nb_mutex, sort to util/, and some other cleanup stuff

git-svn-id: file:///svn/toku/tokudb@48763 c7de825b-a66e-492c-adef-691d508d4ae1