Added untested Event#try? method.
Added untested Dereferenceable#value= method.
Added Mutex and :rescue_exception option to SafeTaskExecutor.
Timers now pass options to the task blocks (untested).
Fixed minor bug in Executor#wait_for_timeout.
Minor test updates to Runnable shared specs.
Rewritten TimerTask now an Executor instead of a Runnable.
Merge branch 'master' into refactor/tasks
Added AtomicBoolean class
Updated TimerTask ti use an AtomicBoolean rather than an AtomicFixnum.
Merge branch 'master' into refactor/tasks
TimerSet now uses SingleThreadExecutor instead of a pure Ruby thread.
Fixed intermittently failing RubyThreadPoolExecutor spec.
OptionsParser::get_executor_from is now a module function.
SimpleActorRef now uses SingleThreadExecutor.
Redefined actor reset behavior.
Fixed or deprecated all remaining pending specs.