smartpanel : updates menu buttons

- set the same style to all buttons.

Change-Id: Id70e6d0121521a45686b04ca6a86e75514b8089e
Tuleap: #790
diff --git a/MainPage.xaml b/MainPage.xaml
index 40fcbd1..9cfd2d7 100644
--- a/MainPage.xaml
+++ b/MainPage.xaml
@@ -113,6 +113,8 @@
                                 <!-- hamburger button. -->

                                 <Button x:Name="_toggleSmartBoxButton_"

                                         Grid.Row="0"

+                                        FontWeight="Bold"

+                                        FontSize="20"

                                         Content="&#xE700;"

                                         Click="_toggleSmartBoxButton__Click"

                                         HorizontalAlignment="Center"