Don't redirect stdout/stderr when BACKGROUND=true

Ruby 1.9's Process.daemon redirects stderr/stdout to /dev/null
which makes logging impossible. This change prevents
Process.daemon from redirecting stderr and stout to /dev/null
unless ENV['MUTE'] is set.
#157 delayed_queue_peek off by one error
Merge branch 'master' of github.com:bvandenbos/resque-scheduler
Fixing potential job-loss race condition
readme update
readme update
releasing 2.0.0
Update master
Merge pull request #168 from coffeencoke/patch-1

Update master
Adding locking to support master fail over
Adding test cases
Merge branch 'master' into locking
updating readme and comments
spelling
readme
readme
typo
readme
spelling ftw
releasing master lock on shutdown, changing lock key