ScriptedInfo|Default Style: Use a 'self' variable consistently

Embedded scripts in a ScriptedInfo document would use the special
'__this__' variable to refer to the current object. This was changed
to 'self' to be consistent with the new class mechanism.
libappfw|LabelWidget: Specify maximum text width with a Rule
libappfw|PopupWidget: By default, blur popup backgrounds

This does have a perf hit currently.
libappfw: Added a new "annotation" semantic for UI items

This is useful in PopupMenuWidget to specify items that provide
additional information in addition to being separators.
UI|Console: Annotated console menu, moved metadata option there

The console menu now has headings and annotations for clarity, and
to explain the more obscure settings. The "Show Metadata" option
belong here, also.

Todo: Other menus could use some headings and annotations, too.
libappfw|PopupMenuWidget: Improved appearance of menu annotations
Refactor|GuiWidget: Added widget attributes

GuiWidget attributes are behavioral flags applicable to any GuiWidget.

Fixed an opacity animation issue when toggling console command and
Doomsday Script modes, where the text editor widget would fade from
zero.
Fixed|Windows: "-userdir" path encoding regression

QDir::cleanPath() takes a QString as argument, and QString implicitly
converts C strings as Latin-1 (!).

Here we can pass the C string path directly to NativePath::setWorkPath()
relying on the automatic conversion to NativePath (that happens as UTF-8).