Auto focus on buttons in main screen (closes #281)

Vocaluxe/Screens/CScreenMain.cs

@@ -57,6 +57,7 @@ namespace Vocaluxe.Screens
             _Texts[_TextRelease].Visible = true;
             _Statics[_StaticWarningProfiles].Visible = false;
             _Texts[_TextWarningProfiles].Visible = false;
+            _SelectElement(_Buttons[_ButtonSing]);
         }
 
         public override bool HandleInput(SKeyEvent keyEvent)
@@ -105,6 +106,10 @@ namespace Vocaluxe.Screens
                             return false;
 
                         break;
+
+                    case Keys.Escape:
+                        _SelectElement(_Buttons[_ButtonExit]);
+                        break;
                 }
             }
             return true;