immediatelly re-run the idle loop.

initialisation. Async.idle still honours after argument, even if a
wx application is not running.

settings.read returns any specified default value even if there is no
GUI.

Platform.canHaveGui, can be used to tell whether we are able to create a
GUI. Async modified to use platform.haveGui instead of performing its
own test.

already queued to be dropped. More useful when used through idleWhen.

events (if user stops moving the mouse), meaning that idle tasks can get
stuck in the idle queue, and not processed until the next UI
event. Therefore, the idle loop now gets periodically called by a
wx.Timer, in addition to via EVT_IDLE events.

dictate when the actual function is called.

keyword arguments.

TaskThread also doesn't crash when an enqueued task raises an error.

'intent' attribute.

  - New cache module, which implements a simple in-memory cache.
  - Async module defines a 'mutex' decorator, which allows instance
    method access to be made mutually-exclusive

a new thread.

2. ImageWrapper marks its expand coverage task thread as a daemon.

because __taskThread attr does not exist.

optionally be told to calculate data ranges on a separate thread.

to collapse many little expansions (that cover individual volumes) into
a few larger ones (that cover many volumes).

equivalent expansions which pertain to adjacent vectors/slices/volumes.

platform module.

be executed.