fix blurry window icon on Linux

Seems to have been fault of Qt trying to set it, apparently. So just don't set it and leave it to DE to handle it by .desktop file association!!!

(I am losing my fucking sanity a bit perhaps with all these random issues)

Author: p0358

resources/layouts/mainwindow.ui

@@ -16,10 +16,6 @@
   <property name="windowTitle">
    <string>MainWindow</string>
   </property>
-  <property name="windowIcon">
-   <iconset resource="../icons-uncso2.qrc">
-    <normaloff>:/icons/uncso2.svg</normaloff>:/icons/uncso2.svg</iconset>
-  </property>
   <property name="locale">
    <locale language="English" country="UnitedStates"/>
   </property>

sources/uncso2app.cpp

@@ -29,6 +29,9 @@ void CUnCSO2App::SetupSettingsInfo()
     this->setApplicationName( "UnCSO2" );
     this->setDesktopFileName( "tf.harmony.UnCSO2" );
     this->setApplicationVersion( QStringLiteral( UNCSO2_VERSION ) );
+#ifdef _WIN32
+    this->setWindowIcon( QIcon( QStringLiteral( ":/icons/uncso2.svg" ) ) );
+#endif
 }
 
 bool CUnCSO2App::ShouldLoadOwnIcons()