Who Supervises the Supervisor?

BREAKING CHANGES

• Introduction of the Process type which is composed of both Supervisor and
  Worker types
• Replace defWorkerSpec in favor of workerSpec and workerSpecWithDefaults
  to build static workers
• Replace of defWorkerOptions in favor of buildWorkerOptions and
  buildWorkerOptionsWithDefaults to build dynamic workers
• Replace terminateWorker in favor of terminateProcess
• Add supervisorSpec, supervisorSpecWithDefaults to build static supervision
  trees
• Add forkSupervisor, buildSupervisorOptions and
  buildSupervisorOptionsWithDefaults to build dynamic supervision trees
• Replace usage of default records semantics in favor of Lenses
• Add joinCapatazThread to avoid providing direct access to async of root
  supervision tree
• Add getSupervisorProcessId to access the ProcessId of a given Supervisor
  record (for dynamic termination)
• Add getSupervisorAsync to access the Async () record of a supervisor
  process thread
• Add getCapatazTeardown to access the Teardown record of the capataz system
• Move CapatazEvent records to new module Control.Concurrent.Capataz.Event
  to avoid requiring DuplicateRecordFields extension on API users
• Remove WorkerAction alias as it is used for library development
  documentation
• Add capataz-repo-watcher example to showcase static supervision trees
• Update capataz-simple-example unix-process example
• forkCapataz signature now requires name for root supervisor