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/dialog/configbase/configdialogbase.cpp

@@ -65,7 +65,7 @@ ConfigDialogBase::ConfigDialogBase(QWidget *parent)
 void ConfigDialogBase::accept()
 {
 	foreach (ConfigDialogBaseTab *tab, tabs_) {
-		if (!tab->Validate()) {
+		if (!tab->validate()) {
 			return;
 		}
 	}
@@ -73,7 +73,7 @@ void ConfigDialogBase::accept()
 	MultiUndoCommand *command = new MultiUndoCommand();
 
 	foreach (ConfigDialogBaseTab *tab, tabs_) {
-		tab->Accept(command);
+		tab->accept(command);
 	}
 
 	Core::instance()->undo_stack()->push(command, tr("Set Configuration"));
@@ -83,7 +83,7 @@ void ConfigDialogBase::accept()
 	QDialog::accept();
 }
 
-void ConfigDialogBase::AddTab(ConfigDialogBaseTab *tab, const QString &title)
+void ConfigDialogBase::add_tab(ConfigDialogBaseTab *tab, const QString &title)
 {
 	list_widget_->addItem(title);
 	preference_pane_stack_->addWidget(tab);
@@ -91,7 +91,7 @@ void ConfigDialogBase::AddTab(ConfigDialogBaseTab *tab, const QString &title)
 	tabs_.append(tab);
 }
 
-void ConfigDialogBase::SetCurrentTab(int index)
+void ConfigDialogBase::set_current_tab(int index)
 {
 	if (index >= 0 && index < list_widget_->count()) {
 		list_widget_->setCurrentRow(index);

app/dialog/configbase/configdialogbase.h

@@ -19,8 +19,8 @@
 
 ***/
 
-#ifndef CONFIGBASE_H
-#define CONFIGBASE_H
+#ifndef OAK_CONFIGBASE_H
+#define OAK_CONFIGBASE_H
 
 #include <QDialog>
 #include <QListWidget>
@@ -36,7 +36,7 @@ class ConfigDialogBase : public QDialog {
 public:
 	ConfigDialogBase(QWidget *parent = nullptr);
 
-	void SetCurrentTab(int index);
+	void set_current_tab(int index);
 
 private slots:
 	/**
@@ -45,7 +45,7 @@ private slots:
 	virtual void accept() override;
 
 protected:
-	void AddTab(ConfigDialogBaseTab *tab, const QString &title);
+	void add_tab(ConfigDialogBaseTab *tab, const QString &title);
 
 	virtual void AcceptEvent()
 	{
@@ -61,4 +61,4 @@ private:
 
 }
 
-#endif // CONFIGBASE_H
+#endif // OAK_CONFIGBASE_H

app/dialog/configbase/configdialogbasetab.cpp

@@ -24,7 +24,7 @@
 namespace olive
 {
 
-bool ConfigDialogBaseTab::Validate()
+bool ConfigDialogBaseTab::validate()
 {
 	return true;
 }

app/dialog/configbase/configdialogbasetab.h

@@ -19,8 +19,8 @@
 
 ***/
 
-#ifndef PREFERENCESTAB_H
-#define PREFERENCESTAB_H
+#ifndef OAK_PREFERENCESTAB_H
+#define OAK_PREFERENCESTAB_H
 
 #include <QWidget>
 
@@ -34,11 +34,11 @@ class ConfigDialogBaseTab : public QWidget {
 public:
 	ConfigDialogBaseTab() = default;
 
-	virtual bool Validate();
+	virtual bool validate();
 
-	virtual void Accept(MultiUndoCommand *parent) = 0;
+	virtual void accept(MultiUndoCommand *parent) = 0;
 };
 
 }
 
-#endif // PREFERENCESTAB_H
+#endif // OAK_PREFERENCESTAB_H