style: unify identifier naming per updated conventions

Automated with clang-tidy readability-identifier-naming (config added to
.clang-tidy) plus scripted passes, per the updated rules now documented
in CONTRIBUTING.md:

- types (class/struct/enum/alias/template params): PascalCase
- functions, variables, members: snake_case (incl. rational -> Rational)
- private/protected members: trailing underscore; static member
  variables likewise (instance_, available_themes_)
- constants and enum values: snake_case (kLinear -> k_linear,
  F32P -> f32p); ALL_CAPS reserved for macros
- macros: OAK_ prefix (OLIVE_ADD_TEST/OLIVE_ASSERT/OLIVE_CONFIG ->
  OAK_ADD_TEST/OAK_ASSERT/OAK_CONFIG, GL_PREAMBLE -> OAK_GL_PREAMBLE,
  include guards -> OAK_*)
- file names: all lowercase (Current/Plugin/OliveHost/OliveClip/
  OlivePluginInstance -> current/plugin/olivehost/oliveclip/
  oliveplugininstance)
- getters share the member name sans underscore, setters set_foo()
- Qt and third-party (OpenFX) virtual overrides and framework callbacks
  keep their original names (exempt in .clang-tidy)

Manual follow-ups required where automation could not reach:
- string-based QMetaObject/SIGNAL/SLOT references updated to renamed
  methods (AddTask, CreatedFile, DeleteSpecificFile, moveSelectionUp, ...)
- macro bodies referencing renamed methods (OLIVE_CONFIG,
  NODE_DEFAULT_DESTRUCTOR, MANAGEDDISPLAYWIDGET_*)
- self-shadowing locals renamed where signals/methods became same-named
  (size_changed, worker_count, selected_items, import param, filters)
- third_party OFX member/namespace usages restored (OFX::Host::*,
  _created, _clipPrefsDirty, createInstance, clearPersistentMessage)
- STL protocol aliases restored (const_iterator) with .clang-tidy
  ignore rules; qHash overloads restored

Full build and test suite pass: ctest 4/4, ~1960 gtest cases green.

app/widget/colorbutton/colorbutton.cpp

@@ -37,52 +37,52 @@ ColorButton::ColorButton(ColorManager *color_manager, bool show_dialog_on_click,
 
 	if (show_dialog_on_click) {
 		connect(this, &ColorButton::clicked, this,
-				&ColorButton::ShowColorDialog);
+				&ColorButton::show_color_dialog);
 	}
 
-	SetColor(Color(1.0f, 1.0f, 1.0f));
+	set_color(Color(1.0f, 1.0f, 1.0f));
 }
 
-const ManagedColor &ColorButton::GetColor() const
+const ManagedColor &ColorButton::get_color() const
 {
 	return color_;
 }
 
-void ColorButton::SetColor(const ManagedColor &c)
+void ColorButton::set_color(const ManagedColor &c)
 {
 	color_ = c;
 
 	color_.set_color_input(
-		color_manager_->GetCompliantColorSpace(color_.color_input()));
+		color_manager_->get_compliant_color_space(color_.color_input()));
 	color_.set_color_output(
-		color_manager_->GetCompliantColorSpace(color_.color_output()));
+		color_manager_->get_compliant_color_space(color_.color_output()));
 
-	UpdateColor();
+	update_color();
 }
 
-void ColorButton::ShowColorDialog()
+void ColorButton::show_color_dialog()
 {
 	if (!dialog_open_) {
 		dialog_open_ = true;
 		ColorDialog *cd = new ColorDialog(color_manager_, color_, this);
 
 		connect(cd, &ColorDialog::finished, this,
-				&ColorButton::ColorDialogFinished);
+				&ColorButton::color_dialog_finished);
 
 		cd->show();
 	}
 }
 
-void ColorButton::ColorDialogFinished(int e)
+void ColorButton::color_dialog_finished(int e)
 {
 	ColorDialog *cd = static_cast<ColorDialog *>(sender());
 
 	if (e == QDialog::Accepted) {
-		color_ = cd->GetSelectedColor();
+		color_ = cd->get_selected_color();
 
-		UpdateColor();
+		update_color();
 
-		emit ColorChanged(color_);
+		emit color_changed(color_);
 	}
 
 	cd->deleteLater();
@@ -90,12 +90,12 @@ void ColorButton::ColorDialogFinished(int e)
 	dialog_open_ = false;
 }
 
-void ColorButton::UpdateColor()
+void ColorButton::update_color()
 {
-	color_processor_ = ColorProcessor::Create(
+	color_processor_ = ColorProcessor::create(
 		color_manager_, color_.color_input(), color_.color_output());
 
-	QColor managed = QtUtils::toQColor(color_processor_->ConvertColor(color_));
+	QColor managed = QtUtils::to_q_color(color_processor_->convert_color(color_));
 
 	setStyleSheet(QStringLiteral("%1--ColorButton {background: %2;}")
 					  .arg(MACRO_VAL_AS_STR(olive), managed.name()));

app/widget/colorbutton/colorbutton.h

@@ -19,8 +19,8 @@
 
 ***/
 
-#ifndef COLORBUTTON_H
-#define COLORBUTTON_H
+#ifndef OAK_COLORBUTTON_H
+#define OAK_COLORBUTTON_H
 
 #include <QPushButton>
 
@@ -40,21 +40,21 @@ public:
 	{
 	}
 
-	const ManagedColor &GetColor() const;
+	const ManagedColor &get_color() const;
 
 public slots:
-	void SetColor(const ManagedColor &c);
+	void set_color(const ManagedColor &c);
 
 signals:
-	void ColorChanged(const ManagedColor &c);
+	void color_changed(const ManagedColor &c);
 
 private slots:
-	void ShowColorDialog();
+	void show_color_dialog();
 
-	void ColorDialogFinished(int e);
+	void color_dialog_finished(int e);
 
 private:
-	void UpdateColor();
+	void update_color();
 
 	ColorManager *color_manager_;
 
@@ -67,4 +67,4 @@ private:
 
 }
 
-#endif // COLORBUTTON_H
+#endif // OAK_COLORBUTTON_H