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.
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
Change: STDOUT.sync = true
releasing master lock on shutdown, changing lock key
Get a better redis-server in test.

The previous implementation was causing intermittent seg faults on my
machine.
Refactor locking, and allow for different locks.

This is work-in-progress: tests fail on Redis 2.6
Merge pull request #177 from dbalatero/resilent_2.4_locking

Resilient 2.4 locking
Allowing custom job classes to be used in Resque.enqueue_at by calling #scheduled on the class. This fixes https://github.com/quirkey/resque-status/issues/51.
Remove redis.keys from remove_delayed