ui: disable native OS styling

There really isn't much point to maintaining this and it directly opposes Qt's code so we'll be fighting them forever

app/ui/style/style.cpp

@@ -38,19 +38,6 @@ QString StyleManager::current_style_;
 QMap<QString, QString> StyleManager::available_themes_;
 QPalette StyleManager::platform_palette_;
 
-void StyleManager::UseOSNativeStyling(QWidget *widget)
-{
-#if defined(Q_OS_WINDOWS)
-  QStyle* s = QStyleFactory::create(QStringLiteral("windowsvista"));
-  widget->setStyle(s);
-  widget->setPalette(platform_palette_);
-#elif defined(Q_OS_MAC)
-  QStyle* s = QStyleFactory::create(QStringLiteral("macintosh"));
-  widget->setStyle(s);
-  widget->setPalette(platform_palette_);
-#endif
-}
-
 QPalette StyleManager::ParsePalette(const QString& ini_path)
 {
   QSettings ini(ini_path, QSettings::IniFormat);

app/ui/style/style.h

@@ -36,8 +36,6 @@ public:
 
   static void SetStyle(const QString& style_path);
 
-  static void UseOSNativeStyling(QWidget* widget);
-
   static const char* kDefaultStyle;
 
   static const QMap<QString, QString>& available_themes()

app/widget/colorlabelmenu/colorlabelmenuitem.cpp

@@ -41,7 +41,6 @@ ColorLabelMenuItem::ColorLabelMenuItem(QWidget* parent) :
   layout->addWidget(box_);
 
   label_ = new QLabel();
-  StyleManager::UseOSNativeStyling(label_);
   layout->addWidget(label_);
 }
 

app/widget/menu/menu.cpp

@@ -106,9 +106,6 @@ void Menu::Init()
   QPalette p = palette();
   p.setColor(QPalette::Disabled, QPalette::Light, QColor(0, 0, 0, 0));
   setPalette(p);
-
-  // If a native palette is available, it should override the one above
-  StyleManager::UseOSNativeStyling(this);
 }
 
 }

app/window/mainwindow/mainmenu.cpp

@@ -42,8 +42,6 @@ namespace olive {
 MainMenu::MainMenu(MainWindow *parent) :
   QMenuBar(parent)
 {
-  StyleManager::UseOSNativeStyling(this);
-
   //
   // FILE MENU
   //