test: Changed ProjectSettingsTestSuite to SettingsTestSuite and extended it substantially

src/lib/Settings.cpp

@@ -6,6 +6,7 @@
 
 Settings::Settings()
 {
+	clear();
 }
 
 Settings::~Settings()

src/lib/Settings.h

@@ -16,6 +16,7 @@ public:
 	void save(const std::string& filePath);
 	void clear();
 
+protected:
 	template<typename T>
 	T getValue(const std::string& key, T defaultValue) const;