Merge pull request #3020 from adrpac/master

Fix Rails 4 detection
No need for instance vars on these tests
Simplify test that verifies multiple warden blocks
Update README.md

The old Michael Hartl's online book link was broken. I guess this link is its substitute.
Merge pull request #3024 from diegosouzapb/master

Update README.md
Silence the OmniAuth logger during tests.
Update dependencies.
* Allows CSRF cleanup to be turned off for certain strategy types
* Defaults Authenticatable CSRF cleanup
lock_access! better failure message
lock_access! better failure message
Document that we can configure Devise test helpers in spec_helper.rb

Closes #3006 [ci skip]
Merge pull request #3023 from jphenow/omniauth-cant-cleanup-csrf

Omniauth can't cleanup CSRF
Merge pull request #3029 from randoum/master

lock_access! better failure message