more font improvements and cleanup

Get rid of the notion of a font's "ascent"; the reference point for
drawing is the top-left corner of the character box rather than the
baseline.  Add some more space between the menu entries and make the
highlight bar around the text.

Replace the default font.png with two images; the build system will
include one or the other based on the resolutions of the device.

Restore the original compiled-in bitmap font, to fall back on when
font.png can't be found (eg, in the charger binary).

Add support for bold text (when a font.png image is used).

Change-Id: I6d211a486a3636f20208502b1cd2aeae8b9f5b02
diff --git a/screen_ui.h b/screen_ui.h
index 8005172..fe0de46 100644
--- a/screen_ui.h
+++ b/screen_ui.h
@@ -76,7 +76,7 @@
     bool pagesIdentical;
     static const int kMaxCols = 96;
-    static const int kMaxRows = 32;
+    static const int kMaxRows = 96;
     // Log text overlay, displayed when a magic key is pressed
     char text[kMaxRows][kMaxCols];
@@ -100,7 +100,6 @@
     void draw_install_overlay_locked(int frame);
     void draw_background_locked(Icon icon);
     void draw_progress_locked();
-    void draw_text_line(int row, const char* t);
     void draw_screen_locked();
     void update_screen_locked();
     void update_progress_locked();