Additionally:
* Added the DimShowLine preference. Layout of the tab will be updated later.
* Improved handling of DraftAnnotationScale preference: catch division by zero and use it for the default anno style.
These style properties are used by `ViewProviderDraftAnnotation`
and by the Gui Command `Draft_AnnotationStyleEditor`.
Therefore, they are moved from `draftguitools.gui_annotationstyleeditor`
module to the `draftutils.utils` module, so that they
are in a central location where they won't cause circular
dependencies.
Introduced in 1b887fa0f5, 4555a77663, 5b3fea59e0.
Make it PEP8 compliant, and shorten line lengths.
It is based on `GuiCommandSimplest` to inherit basic behavior
such as `IsActive` returning `True` when a document exists.