notifier::ProcessId -> ProcessMeta.
ProcessMeta integration.
detail::execution::async_process_group_detail::ExecutionMonitor refactoring.
detail::execution::async_process_group_detail::ProcessGroupStarter style fix.
ProcessMeta: operator<<() implementation.
detail::execution::async_process_group_detail refactoring.
CMakeLists.txt refactoring.
Notifier integration.