Makes the shepherd's task list a private instance, as opposed to a static one. This was a vestige from the previous architecture that we forgot to cleanup. Also adds a call to tasks.clear() when shutting down a MondrianServer instance.
Makes the shepherd's task list a private instance, as opposed to a static one. This was a vestige from the previous architecture that we forgot to cleanup. Also adds a call to tasks.clear() when shutting down a MondrianServer instance.

citycloud-bigdata/mondrian,citycloud-bigdata/mondrian,citycloud-bigdata/mondrian