0.2.14

• Fix: Fixed Task.path to always return a path with forward slashes.
• New: Introducing EntityGroups that lets one to group a bunch of
  SimpleEntitys together, it can be used in grouping tasks even if they are
  in different places on the project task hierarchy or even in different
  projects.
• Update: Task.percent_complete is now correctly calculated for a
  Duration based task by using the Task.start and Task.end
  attribute values.
• Fix: Fixed stalker.models.task.update_time_log_task_parents_for_end()
  event to work with SQLAlchemy v1.0.
• New: Added an option called __dag_cascade__ to the DAGMixin to
  control cascades on mixed in class. The default value is "all, delete".
  Change it to "save-update, merge" if you don't want the children also be
  deleted when the parent is deleted.
• Fix: Fixed a bug in Version class that occurs when a version instance
  that is a parent of other version instances is deleted, the child versions
  are also deleted (fixed through DAGMixin class).