This change does two things:
- it increases the gridUnit to 11 pixel on 102DPI, 18 on 170DPI. This
means on the one hand larger sizing, but aligns gridUnit and
theme.largeSpacing consistently, and thus makes these types work
together better.
- it scales the gridUnit with the DPI. The width of the font's bounding
box doesn't change on the displays I've tried, the height does.
As a result, gridUnit now scales linearly with the DPI setting.