smaller than the original, seems to work well down to about a scale
of 50%.
* clutter/pango/pangoclutter-fontmap.c:
(pango_clutter_font_map_default_substitute): turn off hinting.
* clutter/pango/pangoclutter-render.c: request linear filtering
instead of nearest neighbour when scaling down.
* tests/test-text.c: replaced test with a a test that renders a sample
grid with various pixel sizes and scales for visual inspection of
text rendering quality.