Updated top-level requires

Author: jdantonio

lib/concurrent.rb

@@ -5,24 +5,23 @@
 require 'concurrent/atomics'
 require 'concurrent/channels'
 require 'concurrent/collections'
+require 'concurrent/errors'
 require 'concurrent/executors'
 require 'concurrent/utilities'
 
 require 'concurrent/actor'
 require 'concurrent/atomic'
-require 'concurrent/lazy_register'
 require 'concurrent/agent'
 require 'concurrent/async'
+require 'concurrent/atomic'
 require 'concurrent/dataflow'
 require 'concurrent/delay'
-require 'concurrent/dereferenceable'
-require 'concurrent/errors'
 require 'concurrent/exchanger'
 require 'concurrent/future'
 require 'concurrent/ivar'
+require 'concurrent/lazy'
+require 'concurrent/lazy_register'
 require 'concurrent/mvar'
-require 'concurrent/obligation'
-require 'concurrent/observable'
 require 'concurrent/promise'
 require 'concurrent/scheduled_task'
 require 'concurrent/timer_task'