Exception handling during job reservation
update some deprecated rspec methods
Merge pull request #540 from tiegz/spec_deps

Update some rspec methods that warn of deprecations.
Specs need to pass against rails 4 for a passing build
Stop testing against ruby 1.8

Ruby 1.8 has been EOL'ed and our build matrix is much bigger than it needs to be
Add more details to the contributing guide
Revert "Parallelize stop and restart to be faster with many workers."

Daemons has major issues dealing with threaded daemonizing
This reverts commit 7757209bb5a85de9ab1c8a5eec4894678c11366e.
Merge remote-tracking branch 'origin/pr/537'
Prevent a worker from entering an infinite backend error loop
Provide a hook for a DJ backend to attempt recovery from a reservation error

An example usage would be for DJ active record to reconnect if mysql "goes away"
Prepare 4.0.0 release

[ci-skip]
Update README.md

fix method signature for failure callback in README
Merge pull request #563 from klochner/master

Update README.md
Add a note about Rails 4 to the README
fix one character typo
Merge pull request #580 from mutley/master

fix one character typo
Fix the link for backends wiki page in README.md
Merge pull request #591 from prakashmurthy/patch-1

Fix the link for backends wiki page in README.md
Adds note about running delayed mailer
Merge pull request #598 from beerlington/patch-1

Adds note about running delayed mailer