UI|Client: Run small text preprocessing tasks synchronously

Label texts are typically quite short, so now TextDrawable carries
out short (<20 chars) wrapping tasks immediately.

Also improved LabelWidget so that it updates the size of the widget
before drawing it, when its text becomes ready for drawing.
Fixed|UI|Client: Alignment issue due unsigned math

The "No LOD" label of a slider was missing because negative values
were interpreted as large positive values.
Fixed|Busy Mode: Screen capture for transition-free busy mode

If there will be no animated transition at the end of the busy mode,
we must capture the entire view because busy mode currently takes
over the entire view. Otherwise, the sidebar would seem to disappear
during busy mode.