[gnome-calculator] Added "text-button" style to the menu button on the header bar

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 9df71dfc65f38d434a32b8d39a51e26307ddb63d
Author: Yosef Or Boczko <yoseforb src gnome org>
Date:   Tue May 20 11:17:37 2014 +0300

    Added "text-button" style to the menu button on the header bar
    
    https://bugzilla.gnome.org/show_bug.cgi?id=730427

 src/math-window.vala |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/src/math-window.vala b/src/math-window.vala
index 32619a4..9b07786 100644
--- a/src/math-window.vala
+++ b/src/math-window.vala
@@ -73,6 +73,7 @@ public class MathWindow : Gtk.ApplicationWindow
         menu_button.add (menu_box);
         menu_button.menu_model = (MenuModel) builder.get_object ("window-menu");
         menu_button.get_style_context ().add_class ("title");
+        menu_button.get_style_context ().add_class ("text-button");
         menu_button.use_popover = true;
         menu_button.relief = Gtk.ReliefStyle.NONE;
         menu_button.show ();