Update notes for submitted changes

* split out scheduler-related classes
* split out System and related classes
* split out VirtManager
* split out task library classes
* split out distro library classes
* split out LabController and related classes
* split out User, Group, and related classes
* split out ConfigItem
* split out Activity base class
* split out database type definitions
* split out SQL utilities and base classes
* convert model.py from module into package
* drop unused tables
* remove star imports