Cleanup project structure

Restructured the project somewhat and cleaned up classes so that things are where they belong. Created "Helpers" folder and put appropriate helper classes in there.

Important things:
- The "GameObject path" methods are now extension methods on UnityEngine.Transform
- Removed AccessTools (Reflection helpers) as there was no use of it. Replaced with ReflectionHelpers class.
- Some improvements to the "Object Reflection" window, should be a bit faster now. Code cleaned up significantly.

src/Windows/UIWindow.cs

@@ -0,0 +1,84 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using Harmony;
+using MelonLoader;
+using UnhollowerBaseLib;
+using UnhollowerRuntimeLib;
+using UnityEngine;
+using UnityEngine.Events;
+using UnityEngine.EventSystems;
+
+namespace Explorer
+{
+    public abstract class UIWindow
+    {
+        public abstract string Name { get; set; }
+
+        public object Target;
+
+        public int windowID;
+        public Rect m_rect = new Rect(0, 0, 550, 700);
+
+        public Vector2 scroll = Vector2.zero;
+
+        public static UIWindow CreateWindow<T>(object target) where T : UIWindow
+        {
+            //var component = (UIWindow)AddToGameObject<T>(Instance.gameObject);
+            var window = Activator.CreateInstance<T>();
+
+            window.Target = target;
+            window.windowID = WindowManager.NextWindowID();
+            window.m_rect = WindowManager.GetNewWindowRect();
+
+            WindowManager.Windows.Add(window);
+
+            window.Init();
+
+            return window;
+        }
+
+        public void DestroyWindow()
+        {
+            try
+            {
+                WindowManager.Windows.Remove(this);
+            }
+            catch (Exception e)
+            {
+                MelonLogger.Log("Exception removing Window from WindowManager.Windows list!");
+                MelonLogger.Log($"{e.GetType()} : {e.Message}\r\n{e.StackTrace}");
+            }
+            //Destroy(this);
+        }
+
+        public abstract void Init();
+        public abstract void WindowFunction(int windowID);
+        public abstract void Update();
+
+        public void OnGUI()
+        {
+            if (CppExplorer.ShowMenu)
+            {
+                var origSkin = GUI.skin;
+
+                GUI.skin = UIStyles.WindowSkin;
+                m_rect = GUI.Window(windowID, m_rect, (GUI.WindowFunction)WindowFunction, Name);
+
+                GUI.skin = origSkin;
+            }
+        }
+
+        public void Header()
+        {
+            GUI.DragWindow(new Rect(0, 0, m_rect.width - 90, 20));
+
+            if (GUI.Button(new Rect(m_rect.width - 90, 2, 80, 20), "<color=red><b>X</b></color>"))
+            {
+                DestroyWindow();
+                return;
+            }
+        }
+    }
+}