Finished scene explorer, lots of cleanups. Inspector and Search left now.

src/Input/IHandleInput.cs

@@ -0,0 +1,17 @@
+using UnityEngine;
+
+namespace ExplorerBeta.Input
+{
+    public interface IHandleInput
+    {
+        void Init();
+
+        Vector2 MousePosition { get; }
+
+        bool GetKeyDown(KeyCode key);
+        bool GetKey(KeyCode key);
+
+        bool GetMouseButtonDown(int btn);
+        bool GetMouseButton(int btn);
+    }
+}