Restructure library and plugins

The "core" macro conditions and actions have been extracted out to the
"base" plugin.

The library now mostly contains functionality which is required across
all plugins and (e.g. definitions for macro segments).

The goal is to reduce the complexity and cross-dependencies and group
the source files in a better way.

This should relsove the "library limit of 65535 objects exceeded" build
issue occuring in some Windows build environments.

lib/utils/variable.hpp

@@ -0,0 +1,86 @@
+#pragma once
+#include "export-symbol-helper.hpp"
+#include "item-selection-helpers.hpp"
+#include "resizing-text-edit.hpp"
+
+#include <string>
+#include <optional>
+#include <QStringList>
+#include <obs.hpp>
+
+namespace advss {
+
+class VariableSelection;
+class VariableSettingsDialog;
+
+class Variable : public Item {
+public:
+	Variable();
+	~Variable();
+	void Load(obs_data_t *obj);
+	void Save(obs_data_t *obj) const;
+	EXPORT std::string Value() const { return _value; }
+	EXPORT std::optional<double> DoubleValue() const;
+	EXPORT std::optional<int> IntValue() const;
+	void SetValue(const std::string &val);
+	void SetValue(double);
+	static std::shared_ptr<Item> Create()
+	{
+		return std::make_shared<Variable>();
+	}
+
+	enum class SaveAction {
+		DONT_SAVE,
+		SAVE,
+		SET_DEFAULT,
+	};
+
+private:
+	SaveAction _saveAction = SaveAction::DONT_SAVE;
+	std::string _value = "";
+	std::string _defaultValue = "";
+
+	friend VariableSelection;
+	friend VariableSettingsDialog;
+};
+
+class ADVSS_EXPORT VariableSettingsDialog : public ItemSettingsDialog {
+	Q_OBJECT
+
+public:
+	VariableSettingsDialog(QWidget *parent, const Variable &);
+	static bool AskForSettings(QWidget *parent, Variable &settings);
+
+private slots:
+	void SaveActionChanged(int);
+
+private:
+	ResizingPlainTextEdit *_value;
+	ResizingPlainTextEdit *_defaultValue;
+	QComboBox *_save;
+};
+
+class ADVSS_EXPORT VariableSelection : public ItemSelection {
+	Q_OBJECT
+
+public:
+	VariableSelection(QWidget *parent = 0);
+	void SetVariable(const std::string &);
+	void SetVariable(const std::weak_ptr<Variable> &);
+};
+
+void SaveVariables(obs_data_t *obj);
+void LoadVariables(obs_data_t *obj);
+
+std::deque<std::shared_ptr<Item>> &GetVariables();
+
+EXPORT Variable *GetVariableByName(const std::string &name);
+EXPORT Variable *GetVariableByQString(const QString &name);
+EXPORT std::weak_ptr<Variable> GetWeakVariableByName(const std::string &name);
+EXPORT std::weak_ptr<Variable> GetWeakVariableByQString(const QString &name);
+std::string GetWeakVariableName(std::weak_ptr<Variable>);
+EXPORT QStringList GetVariablesNameList();
+
+std::chrono::high_resolution_clock::time_point GetLastVariableChangeTime();
+
+} // namespace advss