Keep jruby daemon mode from retrying on a hot restart
Extract version from const.rb in gemspec
Bump to 2.5.1
Return success status to the invoking environment

Daemonizing on JRuby returned an error status to the
invoking environment due to exit! defaulting to a
return status of „false“ in constrast to exit which
defaults to „true“.
Merge pull request #357 from yabawock/feature/exit-status

Return success status on daemonizing to the invoking environment
Convince workers to stop by SIGKILL after timeout