Made DiscoverWindow Maps View scrollable / Namespace fixes for 2019.3

Editor/Discover/DiscoverEditor.cs

 using System.Collections.Generic;
 using UnityEngine;
 using UnityEditor;
+#if UNITY_2019_3_OR_NEWER
+using UnityEngine.VFX;
+#else
+#endif
 using UnityEngine.Timeline;
 
 namespace GameplayIngredients.Editor

Editor/Discover/DiscoverWindow.cs

 
             bool hasContent = discoverObjects != null && discoverObjects.Count > 0;
 
-            // Draw Navigation
+            // Draw Navigation Bar
             EditorGUI.BeginDisabledGroup(!hasContent);
             using (new GUILayout.AreaScope(new Rect(discoverAsset.WindowWidth - 168, 8, 160, 20)))
             {
             }
         }
 
+        Vector2 globalContentScroll;
+
+            globalContentScroll = GUILayout.BeginScrollView(globalContentScroll);
             using (new GUILayout.VerticalScope(Styles.indent))
             {
                 GUILayout.Label(discoverAsset.Title, Styles.header);
                 }
             }
             GUILayout.FlexibleSpace();
+            GUILayout.EndScrollView();
         }
 
         Discover selectedDiscover;

Editor/HierarchyHints/HierarchyHints.cs

 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
+#if UNITY_2019_3_OR_NEWER
+using UnityEngine.VFX;
+#else
+#endif
 using UnityEditor;
 using GameplayIngredients.StateMachines;
 using UnityEngine.Playables;