Tasks:
 - Don't attach default progress info callback to sub-tasks.
   (Progress info is channeled upward via the CompositeTasks anyway.)
 - CompositeTasks: automatically re-norm sub-tasks weight to match total 100%
 - Annotator: Cosmetic fix on task progress output
Tasks:
 - Kill "floating" tasks after all.

Annotator & plugins:
 - Plugin init tasks are now created by Annotator's TaskMan now.
   Only a "recipe" is passed back by the plugin.
 - If plugins are added during an asynchronous init process, the resulting
   plugin init tasks are now created as sub-tasks of the pending init task.
   The result is that the init task will only complete when all the plugins
   have been loaded and initialized properly.

dev_async.html:
 - Add demo function showcasing the "wait-for-plugins-too" init promise.

Other:
 - Removed some accidentally added generated files