Adding a scene manger and wal functions

lib/wal/sources/Scene/SceneManager.cpp

@@ -0,0 +1,31 @@
+//
+// Created by Zoe Roux on 2021-05-14.
+//
+
+#include "SceneManager.hpp"
+
+namespace WAL
+{
+	SceneManager &WAL::SceneManager::addScene(WAL::Scene &&scene)
+	{
+		this->_scenes.push_front(scene);
+		return *this;
+	}
+
+	SceneManager &SceneManager::addBackScene(Scene &&scene)
+	{
+		this->_scenes.insert(++this->_scenes.begin(), scene);
+		return *this;
+	}
+
+	Scene &SceneManager::getCurrent()
+	{
+		return this->_scenes.front();
+	}
+
+	SceneManager &SceneManager::closeCurrent()
+	{
+		this->_scenes.pop_front();
+		return *this;
+	}
+}