v2.8.1

A fix for CPU bound tasks run with the exec command of the task manager CLI.

Improvements and fixes

• Running a CPU bound task with exec outside a consumer no longer spawns a
  further subprocess: the command calls the function the task was declared
  with directly, in its own process. A CPU bound task keeps that function
  wherever it is loaded, so the same task object works both in the consumer
  and in the subprocess it spawns
  (#117).
• TaskManager.execute
  accepts in_process=True to run a CPU bound task in the current process
  instead of spawning one for it
  (#117).