Small spacing fixes like imports in separate lines
for more clarity, and the position of the license.
Also use the `ToDo` class with this new name
following Python guidelines.
Properly import the tracker classes. Avoid star imports,
and use the classes prefixed with the name of the module.
The BIM Workbench also has to be updated to use the new
module.
```
import draftguitools.gui_trackers as DraftTrackers
```
