closes #7217

http://unicorn.bogomips.org/Unicorn/Configurator.html#method-i-pid

closes #6411

* .present? is an AS extension that isn't loaded at this point
* single_process_mode is defined in environment, not at the toplevel

Spring is the recommended application preloader for rails

* Get rid of early pathname requirement
* Use require_relative where approciate
* Drop unused files
* Imported new application.rb, environment.rb and environments/* from fresh Rails app
* Cleaned up boot.rb
* Load config in boot.rb
* Deduplicate environments/integration*.rb
* Move username blacklist into defaults.yml
* Ruby 1.9 Hash syntax everywhere
* Reorganize lib/diaspora/markdownify to match conventions
* Get rid of full path requires where possible
* Add dummy content to production section diaspora.yml.example to prevent warning
* Drop sqlite? method
* Move postgres? method into ConfigurationMethods
* Drop token authentication from User

* Dropped all references to Resque
* Moved all jobs under app/workers since that's the Sidekiq convention
* Renamed Jobs module to Worker to match new location
* Adapted all jobs to Sidekiq
* Replaced all enqueue calls with perform_async
* Dropped Resque hacks from specs and features, replaced with
  sidekig/testing in RSpec and sidekig/testing/inline in Cucumber
* Updated scripts to start a Sidekiq server
* Inline Sidekiq sinatra app
* Let Sidekiq create the actual Redis instance
* Workaround already initialized constant warnings in service models
* Resolved ToDo in one job definition by creating proper exception clases
  for some errors in receiving posts
* Added sidekiq section to configuration to make it completly
  configurable to the user
* Add Sidekiq middleware for clean backtraces
* Delay HttpMulti retry to give offline pods a chance to come back up
* Do not retry on GUID already taken and alike errors
* Be graceful about deleted posts in GatherOEmbedData

Pass the real values to stderr_path and stdout_path in unicorn.rb since it runs a case statement on them

* made configuration loader indepenent of rails
* corrected mismatch between example and default config (server.db/server.database)

We are not using REE anymore, so...

* Throw away old system
* Add new system
* Add new example files
* Replace all calls
* add the most important docs
* Add Specs
* rename disable_ssl_requirement to require_ssl
* cloudfiles isn't used/called in our code
* since community_spotlight.list is only used as enable flag replace it with such one and remove all legacy and irelevant codepaths around it
* die if session secret is unset and on heroku
* First basic infrastructure for version information

REDISTOGO_URL is now deprecated in favor of REDIS_URL which is supported by the redis gem too.

add unicorn back in.  only use one worker process for now.  also, move chrome_frame middleware into the correct load path in lib. [ci skip]

This reverts commit 641cedf3.

Revert "Merge pull request #2663 from torrancew/with_unicorn"

This reverts commit 2a2efd09, reversing
changes made to 78978f05.