[gnome-mines] Minimum tile size set to 20 instead of 30 for huge boards (bgo#766144).

[Robert Roth <robertroth src gnome org>]

commit 16888069f960e1cc0f0ad86e61274796c1f58177
Author: Robert Roth <robert roth off gmail com>
Date:   Sun Jun 12 21:42:10 2016 +0300

    Minimum tile size set to 20 instead of 30 for huge boards (bgo#766144).
    
    https://bugzilla.gnome.org/show_bug.cgi?id=766144

 src/minefield-view.vala |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/minefield-view.vala b/src/minefield-view.vala
index 5137b05..35bf876 100644
--- a/src/minefield-view.vala
+++ b/src/minefield-view.vala
@@ -142,8 +142,8 @@ public class MinefieldView : Gtk.Grid
             var w = 320 / minefield.width;
             var h = 200 / minefield.height;
             var s = uint.min (w, h);
-            if (s < 30)
-                s = 30;
+            if (s < 20)
+                s = 20;
             return s;
         }
     }