bench: fix some minor issues
nsq_to_file: allow path separator in filenames

Putting a path separater in filename-format or datetime-format will
cause nsq_to_file to create and fill a directory structure. Useful for
e.g. dumping files in a tree that is easy to import to data warehouse
tools.
Merge pull request #319 from jsocol/nsq_to_file_create_paths

nsq_to_file: allow path separator in filenames
Merge pull request #321 from mreiferson/bench_fixes_321

bench: fix some minor issues
nsqd: shouldnt panic here it's a client error
nsqd: improve IDENTIFY naming

s/long_id/hostname
s/short_id/cid
nsqadmin: update client metadata