code cleanup
ssh connect using host
remove shared gem installation
refactor Job::Queue

* add Helper::TraceShCommand
* trace commands in middlewares (was in queue)
add job::queue#to_script and job::queue#to_before_script
delivery new perform_job message
using before_script and script in job runners
fixes 1.9.3 issue
Merge pull request #7 from evrone/new-jobs

New jobs