closes #6041

Rewrite twitter access-level check

Fixed tests, still working on getting facebook up

Add heroku example to diaspora.example.yml

* 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

Fix empty page after callback from service by redirecting to origin. Also make settings/services page use the same window when authenticating with other services instead of launching a popup.

kill services users with fire. we need this feature, but we need to just start from scratch because this is redonkalonk

OmniAuth callbacks need to accept a raw POST from the auth provider without
verifying the CSRF token, otherwise the session will be reset.

See intridea/omniauth#203
See also http://www.communityguides.eu/articles/16

(This technique will also be needed for API endpoints when the time comes)

MS DG IZ major invite refactor. all tests are green minus weird stuff on dans computer, need to checkout this out on pivots

Bad solution for making sure that an invited facebook user is marked immediately as having been invited