prep 3.2.4
Update Pro-Changes.md
Lock to Celluloid 0.15.2
extracts worker.perform so call can be enhanced

- defines execute_job as an API hook
Helpful comment is helpful
Czech republic proper shortname
pubsub change
added pry-byebug to the sample app
Don't return 404 when no key is provided, redirect to the get request instead.
Update travis to test 2.2.0-preview1
Update web_helpers.rb

fix a bug about zh-cn support.
Use warn for printing TTIN, so people don't configure away the ability to debug
Update .travis.yml
Delete deploy.rb
fix supported rails versions [ci skip]
Use deliver_now in Rails 4.2+, fixes #1933
1933
Deprecated delay extension for ActionMailer 4.2+
More explicit deprecation message
Latest Pro stuff