display MemoryDepth and Depth
Merge pull request #324 from jehiah/nsq_stat_memory_depth_324

nsq_stat column heading missleading
bench.sh isn't rebuilding apps correctly; fix nsqd exit trap too
Made nsqd into an importable package with the daemon program moved to apps/nsdq
Merge pull request #325 from kzvezdarov/split-nsqd-app

nsqd: make importable
cleanup bench.sh
Merge pull request #326 from mreiferson/bench_fixes_326

cleanup bench.sh