add -v/--version
simplify die logic a bit
make upgrade without zero-downtime more clear
refactor ee.emit() to reply()
refactor cluster.workers[id]
bail out early if not upgrading, keys variable might as well be local to broadcast()
refactor index check for last element
missed kill command
lift out last reply() from for
Merge pull request #18 from ralphtheninja/master

simplify die command logic, add -v, refactor sig() and broadcast()