Renamed the disabled state to "removed". This will make it less confusing with the u/i which describes the suspended as disabled. Added create date and start date to the LessonDTO object.
Removed the "is this tool on the classpath" hack. Now it will throw a ToolException if a tool can't be fine. This will break one of our junit tests but the test will have to be skipped for the moment or rewritten to use a known set of tools.